Muriel Quinet | Université catholique de Louvain (original) (raw)

Papers by Muriel Quinet

Frontiers in Plant Science, Dec 7, 2023

Tomato (Solanum lycopersicum L.) domestication and later introduction into Europe resulted in a g... more Tomato (Solanum lycopersicum L.) domestication and later introduction into Europe resulted in a genetic bottleneck that reduced genetic variation. Crosses with other wild tomato species from the Lycopersicon clade can be used to increase genetic diversity and improve important agronomic traits such as stress tolerance. However, many species in the Lycopersicon clade have intraspecific and interspecific incompatibility, such as gametophytic self-incompatibility and unilateral incompatibility. In this review, we provide an overview of the known incompatibility barriers in Lycopersicon. We begin by addressing the general mechanisms self-incompatibility, as well as more specific mechanisms in the Rosaceae, Papaveraceae, and Solanaceae. Incompatibility in the Lycopersicon clade is discussed, including loss of self-incompatibility, species exhibiting only self-incompatibility and species presenting both self-compatibility and selfincompatibility. We summarize unilateral incompatibility in general and specifically in Lycopersicon, with details on the 'self-compatible x selfincompatible' rule, implications of self-incompatibility in unilateral incompatibility and self-incompatibility-independent pathways of unilateral incompatibility. Finally, we discuss advances in the understanding of compatibility barriers and their implications for tomato breeding.

Introduction: Soil salinization is a major global problem. Tomato (Solanum lycopersicum) is one o... more Introduction: Soil salinization is a major global problem. Tomato (Solanum lycopersicum) is one of the main crops produced in the world and is cultivated in areas affected by salinity. However, it is considered as a glycophyte species and is sensitive to salt stress. Solanum chilense is a wild tomato native to the Atacama Desert and is therefore adapted to harsh environmental conditions, including salinity. It is considered as a promising source of genes for tomato improvement. However, the physiology of abiotic stress resistance remains largely unknown in S. chilense and no studies have investigated the resistance of S. lycopersicum x S. chilense interspecific hybrids and the potential value of their use in harsh environments. Methods: In this study, we compared the salt (0 vs. 100 mM NaCl) resistance of S. lycopersicum, S. chilense and their hybrids at vegetative and reproductive stages. Results: Overall, hybrids showed an intermediate behavior between their parents and a higher salt resistance than S. lycopersicum. Their physiological behavior toward salt stress was sometimes closed to S. lycopersicum and sometimes closed to S. chilense. Their sodium accumulation was intermediate between parents, with a sodium concentration closer to S. lycopersicum than S. chilense in roots, but with an aerial concentration closer to S. chilense than to S. lycopersicum. In inflorescences and fruits, the sodium concentration of hybrids was closer to S. lycopersicum than to S. chilense. Despite a decrease in instantaneous transpiration, the photosynthetic nitrogen use efficiency of hybrids was not decreased by salt stress: our results suggest a greater tolerance to the osmotic phase of salt stress in hybrids compared to the parents. Regarding the reproductive stage, inflorescence production and fruit quality were not affected by salt in hybrids. Discussion: This study highlights the potential use of hybrids in improving tomato for salt stress resistance.

Physiologia Plantarum, 2008

Journal of the Science of Food and Agriculture, May 13, 2021

BACKGROUNDAmaranthus cruentus is a promising leafy vegetable with high nutritional value and is a... more BACKGROUNDAmaranthus cruentus is a promising leafy vegetable with high nutritional value and is able to cope with salt stress but the impact of sodium chloride (NaCl) on its main properties have not been studied in detail. Plants from two contrasting cultivars (Rouge: salt‐tolerant and Locale: salt‐sensitive) were exposed to NaCl (0, 30, 60 and 90 mmol L–1) in nutrient solution for 2 weeks. Plant growth, mineral content, oxidative status and antioxidant concentration, salicylic acid concentration, protein content and amino acid profile were analyzed in the harvested leaves.RESULTSLow dose (30 mmol L–1 NaCl) increased plant growth while Na+ accumulated to higher extent in salt‐sensitive Locale than in salt‐tolerant Rouge. A total of 30 mmol L–1 NaCl increased magnesium (Mg), phosphorus (P) and iron (Fe) content, as well as total antioxidant activity, ascorbate, phenolics, α‐tocopherol and carotenoids content to higher extent in cultivar (cv.) Rouge than in cv. Locale. Low (30 mmol L–1) and moderate salinities (60 mmol L–1) increased γ‐tocopherol and total protein in cv. Locale. They also increased lysine, valine, methionine and proline concentration as well as chemical score of protein in this cultivar. The highest NaCl (90 mmol L–1) dose had a detrimental impact on both cultivars.CONCLUSIONSIt is concluded that A. cruentus is a promising plant species for saline agriculture since moderate doses of salt improve both quantitative and qualitative parameters in cultivar dependent manner. © 2021 Society of Chemical Industry.

InTech eBooks, Oct 12, 2016

Seed priming is a pre-sowing treatment which leads to a physiological state that enables seed to ... more Seed priming is a pre-sowing treatment which leads to a physiological state that enables seed to germinate more efficiently. The majority of seed treatments are based on seed imbibition allowing the seeds to go through the first reversible stage of germination but do not allow radical protrusion through the seed coat. Seeds keeping their desiccation tolerance are then dehydrated and can be stored until final sowing. During subsequent germination, primed seeds exhibit a faster and more synchronized germination and young seedlings are often more vigorous and resistant to abiotic stresses than seedlings obtained from unprimed seeds. Priming often involves soaking seed in predetermined amounts of water or limitation of the imbibition time. The imbibition rate could be somehow controlled by osmotic agents such as PEG and referred as osmopriming. Halopriming implies the use of specific salts while "hormopriming" relies on the use of plant growth regulators. Some physical treatments (UV, cold or heat,..) also provide germination improvement thus suggesting that priming effects are not necessarily related to seed imbibition. A better understanding of the metabolic events taking place during the priming treatment and the subsequent germination should help to use this simple and cheap technology in a more efficient way.

Acta horticulturae, Jun 1, 2022

Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2006

Acta Oecologica-international Journal of Ecology, May 1, 2020

Pear trees require insect pollination among compatible cultivars to set fruit. However, pollen tr... more Pear trees require insect pollination among compatible cultivars to set fruit. However, pollen transfer limitation is the main cause of poor yields in this species, due to low visitation rates and few pollen transfer among compatible cultivars. Assisted pollination using "pollen dispensers" containing precollected compatible pollen fitted into the opening of a beehive could increase yield. We investigated whether stored pollen collected from flowers or bee visitors is suitable for pollinating two European pear (Pyrus communis) cultivars, 'Conférence' and 'Doyenné du Comice'. Pollen collected directly from flowers and indirectly from insects was stored for up to 1 year at 4°C and −20°C. Pollen stored at −20°C showed high viability for both cultivars (60-72%). Consequently, fruit set and fruit diameter using this pollen for pollination was similar to that of fresh pollen. However, the viability of pollen that had been stored at 4°C was low (6%-14%) and fruit diameter was 6.5% lower when flowers were pollinated with pollen stored at 4°C compared to fresh pollen. The viability of beecollected pollen was up to 62% lower than that of pollen collected from flowers. The use of bee-collected pollen as a pollen source resulted in a 48% lower fruit set and 95% lower seed set in 'Conférence' compared to fresh pollen, whereas it did not affect 'Doyenné du Comice' fruit and seed sets. The fruit diameter was smaller when flowers were pollinated with bee-collected pollen than with fresh pollen in both 'Conférence' (54.7 vs. 60.6 mm) and 'Doyenné du Comice' (62.5 vs. 70.0 mm). Therefore, pear pollen collected from flowers and stored at −20°C could successfully be used for alternative pollination without affecting fruit production.

Field Crops Research, Jun 1, 2020

Potato is one of the most important food crops worldwide, having excellent performance in tempera... more Potato is one of the most important food crops worldwide, having excellent performance in temperate regions, with cool nights and adequate water supply. In southern Chile, an increase in air temperature between 1−5°C and a decrease in rainfall by 30-40 % are expected due to climate change. The objective of present study was to evaluate the effect of moderate high temperatures (+3.1 to +6.9°C) during tuber bulking on yield and quality properties of Chilean native and commercial genotypes of potato, under different water availability scenarios. Experiments were carried out under field conditions during two growing seasons. Four treatments were applied: (i) T0H0, at ambient temperature under rainfed conditions; (ii) T1H0, at high temperature under rainfed conditions; (iii) T0H1, at ambient temperature under irrigation conditions; (iv) T1H1, at high temperature under irrigation conditions. Increasing temperature for 40 days during tuber bulking did not induce changes in tuber yield and starch content for the same water scenarios. However, it is suggestes that high temperature could reduce potential yield of potato crop (i.e. under irrigation), braking to the yield gain. The main factor affecting tuber yield, in current and future thermal scenarios of southern Chile was water availability as a consequence of reduction in leaf area duration and intercepted radiation during tuber bulking. Effects on healthy tuber properties as protein content, total phenols and antioxidant activity were dependent on the interaction between the environmental factors evaluated and genotypes.

PLOS ONE, Feb 7, 2012

Tomato is an important crop and hence there is a great interest in understanding the genetic basi... more Tomato is an important crop and hence there is a great interest in understanding the genetic basis of its flowering. Several genes have been identified by mutations and we constructed a set of novel double mutants to understand how these genes interact to shape the inflorescence. It was previously suggested that the branching of the tomato inflorescence depends on the gradual transition from inflorescence meristem (IM) to flower meristem (FM): the extension of this time window allows IM to branch, as seen in the compound inflorescence (s) and falsiflora (fa) mutants that are impaired in FM maturation. We report here that JOINTLESS (J), which encodes a MADS-box protein of the same clade than SHORT VEGETATIVE PHASE (SVP) and AGAMOUS LIKE 24 (AGL24) in Arabidopsis, interferes with this timing and delays FM maturation, therefore promoting IM fate. This was inferred from the fact that j mutation suppresses the high branching inflorescence phenotype of s and fa mutants and was further supported by the expression pattern of J, which is expressed more strongly in IM than in FM. Most interestingly, FA-the orthologue of the Arabidopsis LEAFY (LFY) gene-shows the complementary expression pattern and is more active in FM than in IM. Loss of J function causes premature termination of flower formation in the inflorescence and its reversion to a vegetative program. This phenotype is enhanced in the absence of systemic florigenic protein, encoded by the SINGLE FLOWER TRUSS (SFT) gene, the tomato orthologue of FLOWERING LOCUS T (FT). These results suggest that the formation of an inflorescence in tomato requires the interaction of J and a target of SFT in the meristem, for repressing FA activity and FM fate in the IM.

Plant Science, Feb 1, 2015

Rape seeds primed with −1.2 MPa polyethylene glycol 6000 showed improved germination performance.... more Rape seeds primed with −1.2 MPa polyethylene glycol 6000 showed improved germination performance. To better understand the beneficial effect of osmopriming on seed germination, a global expression profiling method was used to compare, for the first time, transcriptomic and proteomic data for osmoprimed seeds at the crucial phases of priming procedure (soaking, drying), whole priming process and subsequent germination. Brassica napus was used here as a model to dissect the process of osmopriming into its essential components. A total number of 952 genes and 75 proteins were affected during the main phases of priming and postpriming germination. Transcription was not coordinately associated with translation resulting in a limited correspondence between mRNAs level and protein abundance. Soaking, drying and final germination of primed seeds triggered distinct specific pathways since only a minority of genes and proteins were involved in all phases of osmopriming while a vast majority was involved in only one single phase. A particular attention was paid to genes and proteins involved in the transcription, translation, reserve mobilization, water uptake, cell cycle and oxidative stress processes.

Journal of Experimental Botany, May 14, 2010

Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice ... more Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice (Oryza sativa L.) cultivars [I Kong Pao (IKP), salt sensitive; and Pokkali, salt resistant] grown for 5 d and 12 d in nutrient solution in the presence or absence of putrescine (1 mM) and 0, 50, and 100 mM NaCl. The salt-sensitive (IKP) and salt-resistant (Pokkali) cultivars differ not only in their mean levels of putrescine, but also in the physiological functions assumed by this molecule in stressed tissues. Salt stress increased the proportion of conjugated putrescine in salt-resistant Pokkali and decreased it in the salt-sensitive IKP, suggesting a possible protective function in response to NaCl. Activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) involved in putrescine synthesis were higher in salt-resistant Pokkali than in salt-sensitive IKP. Both enzymes were involved in the response to salt stress. Salt stress also increased diamine oxidase (DAO; 1.4.3.6) and polyamine oxidase (PAO EC 1.5.3.11) activities in the roots of salt-resistant Pokkali and in the shoots of salt-sensitive IKP. Gene expression followed by reverse transcription-PCR suggested that putrescine could have a post-translational impact on genes coding for ADC (ADCa) and ODC (ODCa and ODCb) but could induce a transcriptional activation of genes coding for PAO (PAOb) mainly in the shoot of salt-stressed plants. The salt-resistant cultivar Pokkali produced higher amounts of ethylene than the salt-sensitive cultivar IKP, and exogenous putrescine increased ethylene synthesis in both cultivars, suggesting no direct antagonism between polyamine and ethylene pathways in rice.

Ecology and Evolution, May 20, 2020

Water stress and increasing temperatures are two main constraints faced by plants in the context ... more Water stress and increasing temperatures are two main constraints faced by plants in the context of climate change. These constraints affect plant physiology and morphology, including phenology, floral traits, and nectar rewards, thus altering plant–pollinator interactions. We compared the abiotic stress responses of two bee‐pollinated Boraginaceae species, Echium plantagineum, an annual, and Echium vulgare, a biennial. Plants were grown for 5 weeks during their flowering period under two watering regimes (well‐watered and water‐stressed) and three temperature regimes (21, 24, 27°C). We measured physiological traits linked to photosynthesis (chlorophyll content, stomatal conductance, and water use efficiency), and vegetative (leaf number and growth rate) and floral (e.g., flower number, phenology, floral morphology, and nectar production) traits. The physiological and morphological traits of both species were affected by the water and temperature stresses, although the effects were greater for the annual species. Both stresses negatively affected floral traits, accelerating flower phenology, decreasing flower size, and, for the annual species, decreasing nectar rewards. In both species, the number of flowers was reduced by 22%–45% under water stress, limiting the total amount of floral rewards. Under water stress and increasing temperatures, which mimic the effects of climate change, floral traits and resources of bee‐pollinated species are affected and can lead to disruptions of pollination and reproductive success.

European Journal of Agronomy, Nov 1, 2017

European pear (Pyrus communis) requires insect pollination among compatible cultivars for fruit p... more European pear (Pyrus communis) requires insect pollination among compatible cultivars for fruit production. However, most commercial orchards have a limited number of cultivars arranged in monotypic blocks or rows. This can result in insufficient inter-cultivar pollination. We hypothesise that limitations in pollen transfer among cultivars could be explained by both insect behaviour and orchard design. We compared insect activity and pollination efficiency in two European pear cultivars, in orchards with different designs: (i) cultivars alternated in the same row or (ii) cultivars in separate rows. To assess limitations in pollen transfer, we also compared hand pollination with compatible pollen versus open pollination by insects. Insect visitors mainly foraged on neighbouring trees within a row, with few movements across rows (1%). Honey bees (Apis mellifera) and bumble bees (Bombus terrestris) visited significantly more flowers per tree (8.5 vs. 3) and more trees (2.1 vs. 1.3) than solitary bees (Andrena spp.) and hoverflies. Insect visitors deposited large amounts of pollen (∼500 pollen grains) on flower stigmas regardless of the insect type. Cultivar placement affected inter-cultivar pollination; less incompatibility signs were observed when cultivars alternated in the same row (5%) than when cultivars were in separate rows (38%). We observed limitations in pollen transfer as open pollination resulted in significant reduced fruit set, compared with hand pollination, in 'Conférence' (21% vs. 30.7%) and 'Doyenné du Comice' (7.2% vs. 16.8%). The foraging behaviour of the insects limited thus inter-cultivar pollen transfer in the orchards with cultivars in separate rows. Cultivars used for pollination (pollinizers) should be planted in the same rows as the main cultivar to increase inter-cultivar pollination.

New Phytologist, Dec 23, 2003

• Flowering of uniflora (uf), a tomato (Lycopersicon esculentum) mutant which consistently produc... more • Flowering of uniflora (uf), a tomato (Lycopersicon esculentum) mutant which consistently produces solitary flowers instead of inflorescences, is late and highly asynchronous in winter. This puzzling behaviour prompted us to further investigate flowering regulation in this mutant to improve our understanding of UNIFLORA gene function. • Growing plants under different daylengths and light intensities revealed that flowering time in uf is dependent on daily light energy integral. Transferring plants from low to high light energy integrals at different times after sowing showed that the light-conditions effect was stage dependent, suggesting that interactions between light energy integrals and endogenous regulatory pathways affect meristem sensitivity to flowering signals. • Carbohydrate analyses suggested that one of these signals could be sucrose, but other interacting factors are probably generated by the root system, as indicated by grafting experiments. • The UNIFLORA gene thus appears to have a dual role in tomato: floral transition regulation and the maintenance of inflorescence meristem identity.

Scientia Horticulturae, Nov 1, 2023

Acta horticulturae, Jun 1, 2022

Experimental Agriculture, Jan 6, 2012

SUMMARYSalt (NaCl) and matric stress (polyethylene glycol; PEG 6000) impacts on germination were ... more SUMMARYSalt (NaCl) and matric stress (polyethylene glycol; PEG 6000) impacts on germination were analysed in two rapeseed (Brassica napusvaroleiferaDel.) cultivars (Exagone: salt and water stress tolerant; Toccata: salt and water stress sensitive), which had the same imbibition kinetics when incubated in distilled water. Final germination percentage (G) and time to reach 50% G (T50) were affected either by 325 mM NaCl or −0.9 MPa PEG in Toccata but not in Exagone. Cultivars did not differ for protein concentration and protease activity in any germination condition; thus, protein metabolism seems not to be implicated in response to stress. Hydroxurea and cytochalasine-D inhibited germination in Toccata exposed to −0.9 MPa PEG but not in Exagone, suggesting that Exagone tolerance could be due to a lower amount of damaged DNA and lower requirement for DNA replication due to cell elongation rather than cell division for radicle elongation. Soluble sugars concentration increased in salt-stressed seeds from Exagone more than in Toccata and this could have allowed osmotic adjustment and therefore cell elongation despite the presence of external NaCl. Priming treatments with gibberellic acid, kinetin, NaCl and PEG hastened seed germination under control conditions but had no effect or even negative effects on germination under both salt and matric stresses.

Frontiers in Plant Science, Dec 7, 2023

Tomato (Solanum lycopersicum L.) domestication and later introduction into Europe resulted in a g... more Tomato (Solanum lycopersicum L.) domestication and later introduction into Europe resulted in a genetic bottleneck that reduced genetic variation. Crosses with other wild tomato species from the Lycopersicon clade can be used to increase genetic diversity and improve important agronomic traits such as stress tolerance. However, many species in the Lycopersicon clade have intraspecific and interspecific incompatibility, such as gametophytic self-incompatibility and unilateral incompatibility. In this review, we provide an overview of the known incompatibility barriers in Lycopersicon. We begin by addressing the general mechanisms self-incompatibility, as well as more specific mechanisms in the Rosaceae, Papaveraceae, and Solanaceae. Incompatibility in the Lycopersicon clade is discussed, including loss of self-incompatibility, species exhibiting only self-incompatibility and species presenting both self-compatibility and selfincompatibility. We summarize unilateral incompatibility in general and specifically in Lycopersicon, with details on the 'self-compatible x selfincompatible' rule, implications of self-incompatibility in unilateral incompatibility and self-incompatibility-independent pathways of unilateral incompatibility. Finally, we discuss advances in the understanding of compatibility barriers and their implications for tomato breeding.

Introduction: Soil salinization is a major global problem. Tomato (Solanum lycopersicum) is one o... more Introduction: Soil salinization is a major global problem. Tomato (Solanum lycopersicum) is one of the main crops produced in the world and is cultivated in areas affected by salinity. However, it is considered as a glycophyte species and is sensitive to salt stress. Solanum chilense is a wild tomato native to the Atacama Desert and is therefore adapted to harsh environmental conditions, including salinity. It is considered as a promising source of genes for tomato improvement. However, the physiology of abiotic stress resistance remains largely unknown in S. chilense and no studies have investigated the resistance of S. lycopersicum x S. chilense interspecific hybrids and the potential value of their use in harsh environments. Methods: In this study, we compared the salt (0 vs. 100 mM NaCl) resistance of S. lycopersicum, S. chilense and their hybrids at vegetative and reproductive stages. Results: Overall, hybrids showed an intermediate behavior between their parents and a higher salt resistance than S. lycopersicum. Their physiological behavior toward salt stress was sometimes closed to S. lycopersicum and sometimes closed to S. chilense. Their sodium accumulation was intermediate between parents, with a sodium concentration closer to S. lycopersicum than S. chilense in roots, but with an aerial concentration closer to S. chilense than to S. lycopersicum. In inflorescences and fruits, the sodium concentration of hybrids was closer to S. lycopersicum than to S. chilense. Despite a decrease in instantaneous transpiration, the photosynthetic nitrogen use efficiency of hybrids was not decreased by salt stress: our results suggest a greater tolerance to the osmotic phase of salt stress in hybrids compared to the parents. Regarding the reproductive stage, inflorescence production and fruit quality were not affected by salt in hybrids. Discussion: This study highlights the potential use of hybrids in improving tomato for salt stress resistance.

Physiologia Plantarum, 2008

Journal of the Science of Food and Agriculture, May 13, 2021

BACKGROUNDAmaranthus cruentus is a promising leafy vegetable with high nutritional value and is a... more BACKGROUNDAmaranthus cruentus is a promising leafy vegetable with high nutritional value and is able to cope with salt stress but the impact of sodium chloride (NaCl) on its main properties have not been studied in detail. Plants from two contrasting cultivars (Rouge: salt‐tolerant and Locale: salt‐sensitive) were exposed to NaCl (0, 30, 60 and 90 mmol L–1) in nutrient solution for 2 weeks. Plant growth, mineral content, oxidative status and antioxidant concentration, salicylic acid concentration, protein content and amino acid profile were analyzed in the harvested leaves.RESULTSLow dose (30 mmol L–1 NaCl) increased plant growth while Na+ accumulated to higher extent in salt‐sensitive Locale than in salt‐tolerant Rouge. A total of 30 mmol L–1 NaCl increased magnesium (Mg), phosphorus (P) and iron (Fe) content, as well as total antioxidant activity, ascorbate, phenolics, α‐tocopherol and carotenoids content to higher extent in cultivar (cv.) Rouge than in cv. Locale. Low (30 mmol L–1) and moderate salinities (60 mmol L–1) increased γ‐tocopherol and total protein in cv. Locale. They also increased lysine, valine, methionine and proline concentration as well as chemical score of protein in this cultivar. The highest NaCl (90 mmol L–1) dose had a detrimental impact on both cultivars.CONCLUSIONSIt is concluded that A. cruentus is a promising plant species for saline agriculture since moderate doses of salt improve both quantitative and qualitative parameters in cultivar dependent manner. © 2021 Society of Chemical Industry.

InTech eBooks, Oct 12, 2016

Seed priming is a pre-sowing treatment which leads to a physiological state that enables seed to ... more Seed priming is a pre-sowing treatment which leads to a physiological state that enables seed to germinate more efficiently. The majority of seed treatments are based on seed imbibition allowing the seeds to go through the first reversible stage of germination but do not allow radical protrusion through the seed coat. Seeds keeping their desiccation tolerance are then dehydrated and can be stored until final sowing. During subsequent germination, primed seeds exhibit a faster and more synchronized germination and young seedlings are often more vigorous and resistant to abiotic stresses than seedlings obtained from unprimed seeds. Priming often involves soaking seed in predetermined amounts of water or limitation of the imbibition time. The imbibition rate could be somehow controlled by osmotic agents such as PEG and referred as osmopriming. Halopriming implies the use of specific salts while "hormopriming" relies on the use of plant growth regulators. Some physical treatments (UV, cold or heat,..) also provide germination improvement thus suggesting that priming effects are not necessarily related to seed imbibition. A better understanding of the metabolic events taking place during the priming treatment and the subsequent germination should help to use this simple and cheap technology in a more efficient way.

Acta horticulturae, Jun 1, 2022

Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2006

Acta Oecologica-international Journal of Ecology, May 1, 2020

Pear trees require insect pollination among compatible cultivars to set fruit. However, pollen tr... more Pear trees require insect pollination among compatible cultivars to set fruit. However, pollen transfer limitation is the main cause of poor yields in this species, due to low visitation rates and few pollen transfer among compatible cultivars. Assisted pollination using "pollen dispensers" containing precollected compatible pollen fitted into the opening of a beehive could increase yield. We investigated whether stored pollen collected from flowers or bee visitors is suitable for pollinating two European pear (Pyrus communis) cultivars, 'Conférence' and 'Doyenné du Comice'. Pollen collected directly from flowers and indirectly from insects was stored for up to 1 year at 4°C and −20°C. Pollen stored at −20°C showed high viability for both cultivars (60-72%). Consequently, fruit set and fruit diameter using this pollen for pollination was similar to that of fresh pollen. However, the viability of pollen that had been stored at 4°C was low (6%-14%) and fruit diameter was 6.5% lower when flowers were pollinated with pollen stored at 4°C compared to fresh pollen. The viability of beecollected pollen was up to 62% lower than that of pollen collected from flowers. The use of bee-collected pollen as a pollen source resulted in a 48% lower fruit set and 95% lower seed set in 'Conférence' compared to fresh pollen, whereas it did not affect 'Doyenné du Comice' fruit and seed sets. The fruit diameter was smaller when flowers were pollinated with bee-collected pollen than with fresh pollen in both 'Conférence' (54.7 vs. 60.6 mm) and 'Doyenné du Comice' (62.5 vs. 70.0 mm). Therefore, pear pollen collected from flowers and stored at −20°C could successfully be used for alternative pollination without affecting fruit production.

Field Crops Research, Jun 1, 2020

Potato is one of the most important food crops worldwide, having excellent performance in tempera... more Potato is one of the most important food crops worldwide, having excellent performance in temperate regions, with cool nights and adequate water supply. In southern Chile, an increase in air temperature between 1−5°C and a decrease in rainfall by 30-40 % are expected due to climate change. The objective of present study was to evaluate the effect of moderate high temperatures (+3.1 to +6.9°C) during tuber bulking on yield and quality properties of Chilean native and commercial genotypes of potato, under different water availability scenarios. Experiments were carried out under field conditions during two growing seasons. Four treatments were applied: (i) T0H0, at ambient temperature under rainfed conditions; (ii) T1H0, at high temperature under rainfed conditions; (iii) T0H1, at ambient temperature under irrigation conditions; (iv) T1H1, at high temperature under irrigation conditions. Increasing temperature for 40 days during tuber bulking did not induce changes in tuber yield and starch content for the same water scenarios. However, it is suggestes that high temperature could reduce potential yield of potato crop (i.e. under irrigation), braking to the yield gain. The main factor affecting tuber yield, in current and future thermal scenarios of southern Chile was water availability as a consequence of reduction in leaf area duration and intercepted radiation during tuber bulking. Effects on healthy tuber properties as protein content, total phenols and antioxidant activity were dependent on the interaction between the environmental factors evaluated and genotypes.

PLOS ONE, Feb 7, 2012

Tomato is an important crop and hence there is a great interest in understanding the genetic basi... more Tomato is an important crop and hence there is a great interest in understanding the genetic basis of its flowering. Several genes have been identified by mutations and we constructed a set of novel double mutants to understand how these genes interact to shape the inflorescence. It was previously suggested that the branching of the tomato inflorescence depends on the gradual transition from inflorescence meristem (IM) to flower meristem (FM): the extension of this time window allows IM to branch, as seen in the compound inflorescence (s) and falsiflora (fa) mutants that are impaired in FM maturation. We report here that JOINTLESS (J), which encodes a MADS-box protein of the same clade than SHORT VEGETATIVE PHASE (SVP) and AGAMOUS LIKE 24 (AGL24) in Arabidopsis, interferes with this timing and delays FM maturation, therefore promoting IM fate. This was inferred from the fact that j mutation suppresses the high branching inflorescence phenotype of s and fa mutants and was further supported by the expression pattern of J, which is expressed more strongly in IM than in FM. Most interestingly, FA-the orthologue of the Arabidopsis LEAFY (LFY) gene-shows the complementary expression pattern and is more active in FM than in IM. Loss of J function causes premature termination of flower formation in the inflorescence and its reversion to a vegetative program. This phenotype is enhanced in the absence of systemic florigenic protein, encoded by the SINGLE FLOWER TRUSS (SFT) gene, the tomato orthologue of FLOWERING LOCUS T (FT). These results suggest that the formation of an inflorescence in tomato requires the interaction of J and a target of SFT in the meristem, for repressing FA activity and FM fate in the IM.

Plant Science, Feb 1, 2015

Rape seeds primed with −1.2 MPa polyethylene glycol 6000 showed improved germination performance.... more Rape seeds primed with −1.2 MPa polyethylene glycol 6000 showed improved germination performance. To better understand the beneficial effect of osmopriming on seed germination, a global expression profiling method was used to compare, for the first time, transcriptomic and proteomic data for osmoprimed seeds at the crucial phases of priming procedure (soaking, drying), whole priming process and subsequent germination. Brassica napus was used here as a model to dissect the process of osmopriming into its essential components. A total number of 952 genes and 75 proteins were affected during the main phases of priming and postpriming germination. Transcription was not coordinately associated with translation resulting in a limited correspondence between mRNAs level and protein abundance. Soaking, drying and final germination of primed seeds triggered distinct specific pathways since only a minority of genes and proteins were involved in all phases of osmopriming while a vast majority was involved in only one single phase. A particular attention was paid to genes and proteins involved in the transcription, translation, reserve mobilization, water uptake, cell cycle and oxidative stress processes.

Journal of Experimental Botany, May 14, 2010

Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice ... more Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice (Oryza sativa L.) cultivars [I Kong Pao (IKP), salt sensitive; and Pokkali, salt resistant] grown for 5 d and 12 d in nutrient solution in the presence or absence of putrescine (1 mM) and 0, 50, and 100 mM NaCl. The salt-sensitive (IKP) and salt-resistant (Pokkali) cultivars differ not only in their mean levels of putrescine, but also in the physiological functions assumed by this molecule in stressed tissues. Salt stress increased the proportion of conjugated putrescine in salt-resistant Pokkali and decreased it in the salt-sensitive IKP, suggesting a possible protective function in response to NaCl. Activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) involved in putrescine synthesis were higher in salt-resistant Pokkali than in salt-sensitive IKP. Both enzymes were involved in the response to salt stress. Salt stress also increased diamine oxidase (DAO; 1.4.3.6) and polyamine oxidase (PAO EC 1.5.3.11) activities in the roots of salt-resistant Pokkali and in the shoots of salt-sensitive IKP. Gene expression followed by reverse transcription-PCR suggested that putrescine could have a post-translational impact on genes coding for ADC (ADCa) and ODC (ODCa and ODCb) but could induce a transcriptional activation of genes coding for PAO (PAOb) mainly in the shoot of salt-stressed plants. The salt-resistant cultivar Pokkali produced higher amounts of ethylene than the salt-sensitive cultivar IKP, and exogenous putrescine increased ethylene synthesis in both cultivars, suggesting no direct antagonism between polyamine and ethylene pathways in rice.

Ecology and Evolution, May 20, 2020

Water stress and increasing temperatures are two main constraints faced by plants in the context ... more Water stress and increasing temperatures are two main constraints faced by plants in the context of climate change. These constraints affect plant physiology and morphology, including phenology, floral traits, and nectar rewards, thus altering plant–pollinator interactions. We compared the abiotic stress responses of two bee‐pollinated Boraginaceae species, Echium plantagineum, an annual, and Echium vulgare, a biennial. Plants were grown for 5 weeks during their flowering period under two watering regimes (well‐watered and water‐stressed) and three temperature regimes (21, 24, 27°C). We measured physiological traits linked to photosynthesis (chlorophyll content, stomatal conductance, and water use efficiency), and vegetative (leaf number and growth rate) and floral (e.g., flower number, phenology, floral morphology, and nectar production) traits. The physiological and morphological traits of both species were affected by the water and temperature stresses, although the effects were greater for the annual species. Both stresses negatively affected floral traits, accelerating flower phenology, decreasing flower size, and, for the annual species, decreasing nectar rewards. In both species, the number of flowers was reduced by 22%–45% under water stress, limiting the total amount of floral rewards. Under water stress and increasing temperatures, which mimic the effects of climate change, floral traits and resources of bee‐pollinated species are affected and can lead to disruptions of pollination and reproductive success.

European Journal of Agronomy, Nov 1, 2017

European pear (Pyrus communis) requires insect pollination among compatible cultivars for fruit p... more European pear (Pyrus communis) requires insect pollination among compatible cultivars for fruit production. However, most commercial orchards have a limited number of cultivars arranged in monotypic blocks or rows. This can result in insufficient inter-cultivar pollination. We hypothesise that limitations in pollen transfer among cultivars could be explained by both insect behaviour and orchard design. We compared insect activity and pollination efficiency in two European pear cultivars, in orchards with different designs: (i) cultivars alternated in the same row or (ii) cultivars in separate rows. To assess limitations in pollen transfer, we also compared hand pollination with compatible pollen versus open pollination by insects. Insect visitors mainly foraged on neighbouring trees within a row, with few movements across rows (1%). Honey bees (Apis mellifera) and bumble bees (Bombus terrestris) visited significantly more flowers per tree (8.5 vs. 3) and more trees (2.1 vs. 1.3) than solitary bees (Andrena spp.) and hoverflies. Insect visitors deposited large amounts of pollen (∼500 pollen grains) on flower stigmas regardless of the insect type. Cultivar placement affected inter-cultivar pollination; less incompatibility signs were observed when cultivars alternated in the same row (5%) than when cultivars were in separate rows (38%). We observed limitations in pollen transfer as open pollination resulted in significant reduced fruit set, compared with hand pollination, in 'Conférence' (21% vs. 30.7%) and 'Doyenné du Comice' (7.2% vs. 16.8%). The foraging behaviour of the insects limited thus inter-cultivar pollen transfer in the orchards with cultivars in separate rows. Cultivars used for pollination (pollinizers) should be planted in the same rows as the main cultivar to increase inter-cultivar pollination.

New Phytologist, Dec 23, 2003

• Flowering of uniflora (uf), a tomato (Lycopersicon esculentum) mutant which consistently produc... more • Flowering of uniflora (uf), a tomato (Lycopersicon esculentum) mutant which consistently produces solitary flowers instead of inflorescences, is late and highly asynchronous in winter. This puzzling behaviour prompted us to further investigate flowering regulation in this mutant to improve our understanding of UNIFLORA gene function. • Growing plants under different daylengths and light intensities revealed that flowering time in uf is dependent on daily light energy integral. Transferring plants from low to high light energy integrals at different times after sowing showed that the light-conditions effect was stage dependent, suggesting that interactions between light energy integrals and endogenous regulatory pathways affect meristem sensitivity to flowering signals. • Carbohydrate analyses suggested that one of these signals could be sucrose, but other interacting factors are probably generated by the root system, as indicated by grafting experiments. • The UNIFLORA gene thus appears to have a dual role in tomato: floral transition regulation and the maintenance of inflorescence meristem identity.

Scientia Horticulturae, Nov 1, 2023

Acta horticulturae, Jun 1, 2022

Experimental Agriculture, Jan 6, 2012

SUMMARYSalt (NaCl) and matric stress (polyethylene glycol; PEG 6000) impacts on germination were ... more SUMMARYSalt (NaCl) and matric stress (polyethylene glycol; PEG 6000) impacts on germination were analysed in two rapeseed (Brassica napusvaroleiferaDel.) cultivars (Exagone: salt and water stress tolerant; Toccata: salt and water stress sensitive), which had the same imbibition kinetics when incubated in distilled water. Final germination percentage (G) and time to reach 50% G (T50) were affected either by 325 mM NaCl or −0.9 MPa PEG in Toccata but not in Exagone. Cultivars did not differ for protein concentration and protease activity in any germination condition; thus, protein metabolism seems not to be implicated in response to stress. Hydroxurea and cytochalasine-D inhibited germination in Toccata exposed to −0.9 MPa PEG but not in Exagone, suggesting that Exagone tolerance could be due to a lower amount of damaged DNA and lower requirement for DNA replication due to cell elongation rather than cell division for radicle elongation. Soluble sugars concentration increased in salt-stressed seeds from Exagone more than in Toccata and this could have allowed osmotic adjustment and therefore cell elongation despite the presence of external NaCl. Priming treatments with gibberellic acid, kinetin, NaCl and PEG hastened seed germination under control conditions but had no effect or even negative effects on germination under both salt and matric stresses.