JOURNAL OF PLANT PHYSIOLOGY 2011 alternative splicing (original) (raw)
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A stress responsive alternative splicing mechanism in Citrus clementina leaves
Journal of Plant Physiology, 2011
Chitinases are often considered pathogenesis-related proteins since their activity can be induced by viral infections, fungal and bacterial cell wall components, and also by more general sources of stress such as wounding, salicylic acid, ethylene, auxins and cytokinins. In the present study, comparative proteomic analysis showed the defense-related acidic chitinase II to be specifically induced in Citrus clementina leaves infested by the two-spotted spider mite Tetranychus urticae or treated with MeJA. In parallel, changes in the mRNA profiles of two partially homologous chitinase forms were shown by RT-PCR. In particular, the appearance of an additional cDNA chitinase fragment in T. urticae-infested and MeJA-treated leaves was observed. This finding may indicate a specific regulatory mechanism of chitinase expression. We report evidence for alternative splicing in T. urticae-infested C. clementina, where a premature stop codon after the first 135 amino acids was introduced. We observed inducible chitinase activity after MeJA treatment, indicative of a rapid plant response to infestation. This work provides the first evidence of chitinase alternative splicing in C. clementina. In addition, the presence of the dual-band pattern for chitinase cDNA by RT-PCR may represent a suitable predictive marker for early diagnosis of plant biotic stress.
Effect of chitinase antisense RNA expression on disease susceptibility of Arabidopsis plants
Plant Molecular Biology, 1994
Chitinases accumulate in higher plants upon pathogen attack are capable of hydrolyzing chitin-containing fungal cell walls and are thus implicated as part of the plant defense response to fungal pathogens. To evaluate the relative role of the predominate chitinase (class I, basic enzyme) ofArabidopsis thaliana in disease resistance, transgenic Arabidopsis plants were generated that expressed antisense RNA to the class I chitinase. Young plants or young leaves of some plants expressing antisense RNA had < 10~o of the chitinase levels of control plants. In the oldest leaves of these antisense plants, chitinase levels rose to 37-90~o of the chitinase levels relative to vector control plants, most likely because of accumulation and storage of the enzyme in vacuoles. The rate of infection by the fungal pathogen Botrytis cinerea was measured in detached leaves containing 7-15 ~o of the chitinase levels of control plants prior to inoculation. Antisense RNA was not effective in suppressing induced chitinase expression upon infection as chitinase levels increased in antisense leaves to 47~o of levels in control leaves within 24 hours after inoculation. Leaves from antisense plants became diseased at a slightly faster rate than leaves from control plants, but differences were not significant due to high variability. Although the tendency to increased susceptibility in antisense plants suggests that chitinases may slow the growth of invading fungal pathogens, the overall contribution of chitinase to the inducible defense reponses in Arabidopsis remains unclear.
TREE CHITINASEs stressand developmental-driven gene regulation
In recent years, a considerable number of studies have harnessed the power of genomics to decipher the role of pathogenesis-related (PR) proteins in plant defence against various biotic and abiotic stresses. Chitinases are PR antifungal proteins expressed constitutively at low levels in plants and induced during biotic pressures and are demonstrated to be involved in the plant defence responses. Remarkable induction of chitinase enzymes by various abiotic agents (salicylic acid, jasmonic acid, ethylene and ozone) and biotic components (pathogens, insect pest, fungal cell wall components and oligosaccharides) is well demonstrated in plants. Several reviews on plant chitinase expression during hostpathogen interaction are available for annual species, whilst reports of their expression in tree species are limited to a few woody perennials: Populus, Pinus, Picea, Eucalyptus, Castanea and Pseudotsuga. The aim of this paper is to review the induction of chitinase during various stresses and developmental processes in forest tree species.
Journal of Plant Physiology, 2011
Citrus plants are currently facing biotic and abiotic stresses. Therefore, the characterization of molecular traits involved in the response mechanisms to stress could facilitate selection of resistant varieties. Although large cDNA microarray profiling has been generated in citrus tissues, the available protein expression data are scarce. In this study, to identify differentially expressed proteins in Citrus clementina leaves after infestation by the two-spotted spider mite Tetranychus urticae, a proteome comparison was undertaken using two-dimensional gel electrophoresis. The citrus leaf proteome profile was also compared with that of leaves treated over 0-72 h with methyl jasmonate, a compound playing a key role in the defense mechanisms of plants to insect/arthropod attack. Significant variations were observed for 110 protein spots after spider mite infestation and 67 protein spots after MeJA treatments. Of these, 50 proteins were successfully identified by liquid chromatography-mass spectrometry-tandem mass spectrometry. The majority constituted photosynthesis-and metabolism-related proteins. Five were oxidative stress associated enzymes, including phospholipid glutathione peroxidase, a salt stressed associated protein, ascorbate peroxidase and Mn-superoxide dismutase. Seven were defense-related proteins, such as the pathogenesis-related acidic chitinase, the protease inhibitor miraculin-like protein, and a lectin-like protein. This is the first report of differentially regulated proteins after T. urticae attack and exogenous MeJA application in citrus leaves.
Journal of Plant Physiology, 2001
Chitinases are well-known antifungal proteins and belong to the pathogenesis-related (PR) group of proteins. In the present study, we screened a Valencia orange flavedo cDNA expression library with an antibody raised against a purified Valencia basic chitinase polypeptide and isolated its corresponding cDNA. The Valencia flavedo chitinase cDNA, designated chi1, is 875 bp in length, with an open reading frame of 693 bp. The chi1 gene encodes a predicted polypeptide of 231 amino acids with a predicted molecular mass of 25.1 kDa and a pI of 9. 15. The CHI1 protein shares 60, 58, and 56 % identity with the basic chitinase proteins of rice, grape and maize, respectively. Southern blot analysis indicated that chi1 is present as a low-copy gene. RNA gel blot hybridizations revealed that chi1 gene expression was markedly induced by various treatments that induce fruit resistance against the green mould pathogen Penicillium digitatum (Pers.:Fr.) Sacc. These treatments included elicitation of fruit pathogen resistance by UV irradiation, hot water brushing, and application of β-aminobutyric acid (BABA) and Candida oleophila antagonist yeast cells.
Elicitor-specific induction of one member of the chitinase gene family in Arachis hypogaea
MGG Molecular & General Genetics, 1990
Chitinases are believed to play an important role in plant defence against bacterial and fungal attack. In peanut (Arachis hypogaea)chitinase genes form a small multigene family. Four chitinase cDNAs (chit 1-4) were isolated from cultured peanut cells. Expression of individual chit genes was assayed by the polymerase chain reaction (PCR) followed by analysis of restriction fragment length polymorphisms (RFLP). UV irradiation, dilution of cell cultures and treatment with Phytophthora megasperma (Ping) elicitor or yeast extract were used to induce expression of chit genes. The chit 3 gene is constitutively expressed at a low level in untreated as well as in treated cultures; the expression of chit 4 gene is induced by each of the stimuli tested, whereas the chit i gene is activated by cell culture dilution and by yeast extract treatment. The chit 2 gene is strongly activated by treatment with cell wall components from the fungus Phytophthora megasperrna but not by the other stimuli. These results indicate that chit 2 gene expression may be controlled by pathogen-specific regulatory elements.
Biotechnology reports (Amsterdam, Netherlands), 2017
Chitinases are the hydrolytic enzymes which belong to the pathogenesis-related (PR) protein family and play an important role not only in plant defense but also in various abiotic stresses. However, only a limited number of chitinase genes have been characterised in B. juncea. In this study, we have characterised B. juncea class IV chitinase gene (accession no EF586206) in response to fungal infection, salicylic acid (SA), jasmonic acid (JA) treatments and wounding. Gene expression studies revealed that the transcript levels of Bjchitinase (BjChp) gene increases significantly both in local and distal tissues after Alternaria infection. Bjchitinase gene was also induced by jasmonic acid and wounding but moderately by salicylic acid. A 2.5 kb class IV chitinase promoter of this gene was isolated from B. juncea by Genome walking (accession no KF055403.1). In-silico analysis of this promoter revealed a number of conserved cis-regulatory elements related to defense, wounding and signalli...
FEBS Letters, 1997
Endochitinases are widely distributed among higher plants, including a number of important crop species. They are generally considered to be involved in plant defence against potential pathogens. We have cloned a class IV chitinase gene {AtchitIV) from Arabidopsis thaliana. Southern blot analysis allowed the detection of two cross-hybridising genes in the A. thaliana genome. AtchitIV transcripts are detected in seedpods, but not in roots, inflorescence stems, leaves and flowers of healthy plants. The transcripts accumulated very rapidly in leaves after inoculation with Xanthomonas campestris. Maximum mRNA accumulation was reached one hour after infection and decreased to very low levels 72 hours after induction. This result suggests an involvement of AtchitIV in the initial events of the hypersensitive reaction. Nevertheless, A. thaliana plants transformed with the gus gene under the control of a class IV chitinase bean promoter, showed GUS activity in seed embryos. These data, together with the constitutive expression of the endogenous gene in the seedpods, points to additional physiological roles for this protein.
Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression, 1995
Complementary and genomic DNAs coding for a Brassica napus chitinase have been cloned and sequenced. The genomic DNA contains one intron and encodes a 322-amino acid basic chitinase with a 20-amino acid N-terminal signal peptide followed by a 40-amino acid cysteine-rich domain, linked by a hinge region to the main domain of the enzyme. The sequence of the cDNAs is identical to the exon sequence deduced from the genomic DNA. A probe derived from this gene identified a 1.2-kb transcript present in high amount in roots, moderate in floral tissues and low in stems and leaves. The synthesis of these transcripts is regulated during development and is induced in roots by wounding and ethephon. This type of chitinase is encoded by two sequences in Brassica napus, as shown either by Southern hybridizations or by genomic amplification and sequencing using the polymerase chain reaction. These genes are homologous to one sequence found in the Brassica oleracea genome.