The Importance of Phenolic Metabolism to Limit the Growth of Phakopsora pachyrhizi (original) (raw)
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Biosaintifika: Journal of Biology & Biology Education, 2018
Asian soybean rust caused by Phakopsora pachyrhizi is one of the most destructive foliar diseases on soybean. Severe infection of this disease causes early defoliation and reduces the yield. To determine the response of soybean genotypes to this disease and the changes of metabolites in seeds, a greenhouse study was conducted using eight Indonesian soybean cultivars, i.e. Malabar, Wilis, Ringgit, Pangrango, Argomulyo, Grobogan, Dena 1, and Dena 2. The experiment was arranged in a randomized completely block design and repeated three times. The soybean crops were inoculated with the pathogen and another set was not inoculated. Infection of P. pachyrhizi reduced fresh biomass, seed weight per plant, and weight of 100 seeds. However, total flavonoid contents in seeds increased from 12 to 50% in all infected genotypes. The increase of daidzein from 27 to 67% in seeds was observed, except for Malabar and Argomulyo. The increase of genistein was genotypic dependence. The increase of total phenolic contents as well as antioxidant activity was also depending on the genotypes. P. pachyrhizi could be one of the biotic elicitors to increase total flavonoid contents in soybean seeds. Dena 1 less suffered from the rust infection as represented by the least pustule number, less reduction in seed weight and weight of 100 seeds. Secondary metabolites particularly phenolics and isoflavones in seeds of this cultivar increased significantly after the rust infection. This cultivar could be considered as an alternative tolerant genotype where cultivated area is favorable for soybean rust infection.
Relationship between biochemical and photosynthetic traits with Asian soybean rust
Anais da Academia Brasileira de Ciências, 2018
Asian soybean rust (Phakopsora pachyrhizi-ASR) is one of the major diseases that occur in soybean and causes great damage to commercial crops. Therefore, the goal of this work was to investigate the relationship between biochemical and photosyntetic parameters in soybean with ASR. Two experiments were performed in a randomized complete block with three treatments (water, Tween 20, and methyl jasmonate). The evaluated traits were: severity, chlorophyll pools, concentration of phenolic compounds content, enzyme activity, and photosyntetic parameters. Based on Pearson correlation, correlation network and path analysis it was verified that the severity had high correlation with almost all traits evaluated meanwhile photosynthesis is weakly related with almost all traits. Therefore, the occurrence of ASR affects directly the traits related to enzymatic activity and phenolic compounds content in soybean plants inoculated with ASR. The management of ASR is important to keep in normal levels the rates of photosynthesis carried out by the plant, and thus not affect the yield. Besides that, understanding the biochemical mechanisms and ecophysiological responses that occur during the soybean-P. pachyrhizi interaction has a great importance for breeding programs, as it will help for obtaining resistant cultivars or efficient methods in fungus control.
Chemical-induced resistance against brown stem rot in soybean: the effect of benzothiadiazole
2008
In the present work, the biochemical basis of tolerance in soybean to stem rot via its priming with benzothiadiazole (BTH) was investigated. To evaluate the potentiation of BTH in this respect, differences in the elements associated with the induction of defenses were traced before and after subjecting soybean to biotic stress induced by its inoculation with Phialophora gregata. BTH priming of non-inoculated soybeans was observed to increase percentage of seed germination, fresh and dry weights of shoots and roots and photosynthetic pigments. Marked differences in the phenolics, lignin, flavonoids and the enzymes involved in the regulation of their metabolism namely: phenylalanine ammonia-lyase (PAL), Peroxidase POX and polyphenol oxidase (PPO) were recorded. Leaf tissues of soybeans which were primed with BTH responded differently to pathogen inoculation with Phialophora gregata, compared with both the control and BTH-primed and non-challenged ones. Appreciable increase in the activity level of PAL, POX and PPO was observed in response to challenging of BTH-primed soybean, particularly on applying it as both seed soaking followed by foliar spraying. On the other hand, catalase activity subjected to marked increase in non-challenged, BTH-treated soybeans meanwhile it was obviously decreased upon pathogen inoculation of BTH-treated plants. Appreciable increase in the different forms of phenolics (free, conjugated, cell wall-bound phenolics and total soluble phenols) was recorded in response to BTH-priming and challenging. Moreover, the same treatments induced obvious increase in the flavonoid content of soybean leaves. Thus, a four-fold increase in leuteolin content was observed in treated tissues, compared with the control. Also, the quercetin and genistein content subjected to marked increase in response to BTH and challenging with Phialophora gregata. The bioassay for antifungal activity of phenolic compounds obtained from BTH-primed and challenged soybeans revealed its high toxicity to fungal spore germination. The marvelous changes induced in protein pattern in response to priming soybean with BTH and its challenging with its pathogen, refer to that BTH act at the molecular level and that it induced change at the transcriptional and translational levels.
Organelles Proteomics, 2014
Asian soybean rust (ASR), which is incited by the fungus Phakopsora pachyrhizi, is considered one of the most aggressive diseases to the soybean culture. There are no commercial cultivars immune to the pathogen and the control measure currently used is the application of fungicides that harms the environment and increases production costs. For a better understanding of the host’s response to the pathogen at the molecular level, two soybean genotypes were analyzed (PI561356, resistant to ASR and Embrapa 48, susceptible) at 72 hours and 192 hours after inoculation with spores of P. pachyrhizi. Leaf protein profiles of the plants were compared by two-dimensional electrophoresis associated with mass spectrometry (MS). Twenty-two protein spots presented different levels when the two treatments were compared (inoculated vs. non-inoculated). From those, twelve proteins were identified by MS analysis. Some of them are involved in metabolic pathways related to plant defense against pathogens...
Biochemical Studies in Rust Resistant and Susceptible Genotypes of Soybean
Journal of Plant Pathology & Microbiology, 2020
Biochemical parameters play an important role in resistance or susceptibility in plants against diseases. Development of resistant varieties is the most appropriate approach to control the disease and the concept is now developing to explore the built-in plant defense mechanism in relation to pathogen attack. An attempt was made to study the biochemical factors imparting rust resistance in soybean genotypes at 75 days after sowing (DAS). The resistant genotypes had more of total phenols than susceptible genotypes. Total sugar (Reducing and Non reducing) content was more in resistant genotypes compared to susceptible genotypes at 75 DAS. The resistant genotypes EC- 241780 recorded maximum (5.78 mg/g.) reducing sugar followed by 4.75 mg/g in EC- 241778 (P) genotype and least was recorded 3.31 mg/g in JS-335 susceptible genotype. Among the genotypes EC 241778 recorded highest non reducing sugar content of 2.27 mg g of fresh wt followed by DSb 21 (2.25 mg/g). The least non-reducing suga...
Evaluation of soybean genotypes for resistance to rust disease (Phakopsora pachyrhizi
Pest and disease are one of limiting factor in soybean cultivation in Indonesia. One of the diseases that can reduce soybean production is rust diseases caused by Phakopsora pachyrhizi. The use of resistant varieties can reduce yield losses due to this disease. The aim of this study was to evaluate the resistance of soybean genotypes to rust disease and to study the interaction between agronomic traits with rust disease on soybean genotypes. This study was conducted at a screen house of the Indonesian Legumes and Tuber Crops Research Institute (ILETRI) in Malang, Indonesia from April to July 2015. A total of 10 soybean genotypes consist of eight lines and two varieties (Argomulyo and Grobogan) was evaluated for rust resistance to rust disease. The eight lines tested were a progeny of a cross between offspring of IAC 100 (resistant to rust disease) with high yielding soybean varieties (Argomulyo and Grobogan). The experiment was arranged as randomized completely block design with four replications. Each genotype planted in five plastic pots for each replicate. Three weeks after planting, all plants were inoculated with rust disease. Inoculation was done by spraying a suspension of spores (spore density of 10 4 spore mL-1) to the surface of leaves. Observations were carried out on rust disease severity based on the method of International Working Group on Soybean Rust rating system, days to flowering, plant height, number of branches, number of fertile nodes, number of pods, and seed weight per plant. The results showed that all genotypes classified as moderately resistant to rust disease. In this study, days to flowering and plant height influence the development of rust disease severity. There are three lines that have seed weight per plant significantly heavier than Argomulyo (4.97 g) and Grobogan (4.30 g), namely K/I100//B63///G-7 (6.55 g), K/I100//B63///G-8 (6.15 g), and I100/B54//A-5 (5.85 g). The high value of the scales of seed weight per plant for the three lines is supported by high-performance plants with a lot of number of fertile nodes and pods. These three soybean genotypes potentially serve as genetic material to develop high yielding soybean varieties and resistant to rust disease.
… and Molecular Biology, 2008
Asian soybean rust (ASR), caused by the phytopathogenic fungi Phakopsora pachyrhizi, has caused large reductions in soybean (Glycine max) yield in most locations in Brazil where it has occurred since it was first reported in May 2001. Primary efforts to combat the disease involve the development of resistant cultivars, and four dominant major genes (Rpp1, Rpp2, Rpp3 and Rpp4) controlling resistance to ASR have been reported in the literature. To develop new long-lasting soybean ASR resistance genes, we used field experiments to assess ASR leaf lesion type in 11 soybean genotypes (BR01-18437, BRS 184, BRS 231, BRS 232, BRSGO Chapadões, DM 339, Embrapa 48, PI 200487, PI 230970, PI 459025-A and PI 200526) and the 55 F2 generations derived from their biparental diallel crosses. The results indicated that PI 200487 and PI 200526 carry different dominant resistance major genes which are both different from Rpp2 through Rpp4. Furthermore, resistance to ASR in BR01-18437 is controlled by a single recessive major gene, also different from Rpp1 through Rpp4 and different from the genes in PI 200487 and PI 200526.
Chemical Control of Asian Soybean Rust and Its Effect in the Yield and Quality of Soybean Seeds
Journal of Agricultural Science
The objective of this study was to evaluate the effect of a foliar fungicide commonly used to control Asian soybean rust (Phakopsora pachyrhizi) in the physiological and sanitary quality of soybean seeds. The experiment was carried out during the 2012/13 field season, with six treatments and four replications arranged in a randomized complete block design. The following treatments were evaluated: T1 (no fungicide application); one application at R1 stage; two applications at R1 and R3 stages; three applications at R1, R3, and R5 stages; four applications at R1, R3, R5, and R6 stages and five applications at R1, R3, R5, R6 and R7 stages. Seeds yield, seed weight, viability and vigor assessments were used to measure the impact of foliar fungicide applications on soybean yield and seed quality. The results indicated that four fungicide applications provide higher grain yield, increased seed weight, and germination percentages within commercial standards. In contrast, the number of fung...
2019
ACKNOWLEDGEMENT I take this opportunity to acknowledge the contribution of various parties and persons to the realization of the awesome task of completing this research. First and foremost am highly indebted to God, my creator and redeemer, who made provisions, directly or indirectly through persons every other time for all the needs that arose during the period of my study. I acknowledge and sincerely thank the National commission for Science, Technology and Innovation (NACOSTI) Kenya for providing funds for the research. High appreciation is also made for the dedication of my supervisors Prof. Sheila Okoth, Dr. George Obiero and Dr. Jendeka Mahasi, for their guidance and encouragement throughout my research period. I thank God for their patience. I also acknowledge the input and guidance of the late Prof James Ochanda. I would like to express my gratitude to the technical staff at Centre for Biotechnology and Bioinformatics; University of Nairobi (CEBIB-UON), Ms Anne Owiti and Mr Edwin Rono for their assistance during my research. I also extend my gratitude to the entire staff and students of CEBIB, in one way or the other they have made my work a reality. I would also wish to acknowledge and express my gratitude to the staff at KALRO (Njoro) for making available the seeds used in this study. Special gratitude to the technician Mr. Patrick Mbehero of KALRO, for his assistance during the course of the research. I would also wish to thank the staff from Tropical Soil Biology and Fertility (TSBF) and International Center for Tropical Agriculture (CIAT); Maseno for training on soybean diseases and linking me with the farmers in Western Kenya. I would also wish to thank Mr. Peter Kataka of Khwisero for v his assistance during the field work. Special gratitude to agricultural extension officers and all soybean farmers from Khwisero, Teso, Butere and Mumias sub-counties for their input during field work. I would like to express my deepest gratitude to my late parents Pastor Harrison Ogot and Mrs Sylvia Ogot, my husband Wilys, my daughters Mitchel and Grace and my siblings, Johnson, George, Enock, Peter and Joash for their endless love, moral and financial support that they provided during my study. I also want to acknowledge the support and motivation of my colleagues and friends, their motivation throughout my degree course kept me going. vi