Sequence analysis of sundew chitinase gene (original) (raw)
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Isolation and Characterization of Chitinase Gene from the Untraditional Plant Species
2013
Round-leaf sundew (Drosera rotundifolia L.) from Droseraceae family belongs among a few plant species with strong antifungal potential. It was previously shown that chitinases of carnivorous plant species may play role during the insect prey digestion, when hard chitin skeleton is being decomposed. As many phytopathogenic fungi contain chitin in their cell wall our attention in this work was focused on isolation and in silico characterization of genomic DNA sequence of sundew chitinase gene. Subsequently this gene was fused to strong constitutive CaMV35S promoter and cloned into the plant binary vector pBinPlus and tested in A. tumefaciens LBA 4404 for its stability. Next, when transgenic tobacco plants are obtained, increasing of their antifungal potential will be tested.
Proceedings of the National Academy of Sciences, 1991
Tobacco contains different isoforms of chitinase (EC 3.2.1.14), a hydrolase thought to be involved in the defense against pathogens. Deduced amino acid sequences for putatively vacuolar, basic chitinases differ from the homologous extracellular, acidic isoforms by the presence of a C-terminal extension. To examine the role of this C-terminal extension in protein sorting, Nicotiana silvestris plants were stably transformed with chimeric genes coding for tobacco basic chitinase A with and without the seven C-terminal amino acids. In plants expressing unmodified chitinase A, the enzyme activity was low in the intercellular wash fluid but high in protoplasts and isolated vacuoles. In contrast, in plants expressing mutant chitinase lacking the C terminus, the activity
Structural and functional evolution of chitinase-like proteins from plants
Protein and Peptide Letters, 2015
The plant genome contains a large number of sequences that encode catalytically inactive chitinases referred to as chitinase-like proteins (CLPs). Although CLPs share high sequence and structural homology with chitinases of glycosyl hydrolase 18 (TIM barrel domain) and 19 families, they may lack the binding/catalytic activity. Molecular genetic analysis revealed that gene duplication events followed by mutation in the existing chitinase gene have resulted in the loss of activity. The evidences show that adaptive functional diversification of the CLPs has been achieved through alterations in the flexible regions than in the rigid structural elements. The CLPs plays an important role in the defense response against pathogenic attack, biotic and abiotic stress. They are also involved in the growth and developmental processes of plants. Since the physiological roles of CLPs are similar to chitinase, such mutations have led to plurifunctional enzymes. The biochemical and structural characterization of the CLPs is essential for understanding their roles and to develop potential utility in biotechnological industries. This review sheds light on the structure-function evolution of CLPs from chitinases.
The Plant Journal, 1994
A novel chitinese gene of tobacco was isolated and characterized by DNA sequence analysis of a genomic clone and a cDNA clone. Comparative sequence analysis of both clones showed an identity of 94%. The proteins encoded by these sequences do not correspond to any of the previously characterized plant chitinases of classes I-IV and are designated as class V chitinaeas. Comparison of the chitinese class V paptide sequence with sequences in the Swiss Protein databank revealed significant sequence similarity with bacterial exo-chitinases from Bacillus circulans, Serratla marcescens and Streptomyces plicatus. It was demonstrated that class V chitinase gene expression is Induced after treatment of tobacco with different forms of stress, like TMV-infection, ethylene treatment, wounding or ultraviolet irradiation.
Structural and Evolutionary Relationships Among Chitinases of Flowering Plants
Journal of Molecular Evolution, 1997
The analysis of nuclear-encoded chitinase sequences from various angiosperms has allowed the categorization of the chitinases into discrete classes. Nucleotide sequences of their catalytic domains were compared in this study to investigate the evolutionary relationships between chitinase classes. The functionally distinct class III chitinases appear to be more closely related to fungal enzymes involved in morphogenesis than to other plant chitinases. The ordering of other plant chitinases into additional classes mainly relied on the presence of auxiliary domains—namely, a chitin-binding domain and a carboxy-terminal extension—flanking the main catalytic domain. The results of our phylogenetic analyses showed that classes I and IV form discrete and well-supported monophyletic groups derived from a common ancestral sequence that predates the divergence of dicots and monocots. In contrast, other sequences included in classes I* and II, lacking one or both types of auxiliary domains, were nested within class I sequences, indicating that they have a polyphyletic origin. According to phylogenetic analyses and the calculation of evolutionary rates, these chitinases probably arose from different class I lineages by relatively recent deletion events. The occurrence of such evolutionary trends in cultivated plants and their potential involvement in host–pathogen interactions are discussed.
Current View on Chitinase for Plant Defence
Plant pathogen is serious problem worldwide amongst the crop cultivars. Large number of plants suffers from range of infectious diseases caused by different pathogens, amongst them fungi are responsible for majority of infectious plant diseases that limiting the crop yield and impact the post-harvest quality of food. So it is important to protect the plants from fungal infection. Substantial approaches have been done with fungicides or heavy metals and by conventional breeding for combating the fungal diseases but so far no conclusive solution has been developed. Genetic engineering paves a new way to protect the plants from harmful fungal afflictions by introducing genes encoding chitinase enzyme that degrade the chitin, which are the key component of fungal cell wall.
Journal of Molecular Modeling, 2012
Glycoside hydrolase family 19 chitinases (EC 3.2.1.14) widely distributed in plants, bacteria and viruses catalyse the hydrolysis of chitin and play a major role in plant defense mechanisms and development. Rice possesses several classes of chitinase, out of which a single structure of class I has been reported in PDB to date. In the present study an attempt was made to gain more insight into the structure, function and evolution of class I, II and IV chitinases of GH family 19 from rice. The three-dimensional structures of chitinases were modelled and validated based on available X-ray crystal structures. The structural study revealed that they are highly α-helical and bilobed in nature. These enzymes are single or multi domain and multi-functional in which chitinbinding domain (CBD) and catalytic domain (CatD) are present in class I and IV whereas class II lacks CBD. The CatD possesses a catalytic triad which is thought to be involved in catalytic process. Loop III, which is common in all three classes of chitinases, reflects that it may play a significant role in their function. Our study also confirms that the absence and presence of different loops in GH family 19 of rice may be responsible for various sized products. Molecular phylogeny revealed chitinases in monocotyledons and dicotyledons differed from each other forming two different clusters and may have evolved differentially. More structural study of this enzyme from different plants is required to enhance the knowledge of catalytic mechanism and substrate binding.
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.
An increase in urbanization and industrialization has increased the demand of rapid and sustainable agricultural practices. Alternate practices offering better agricultural productivity are necessary to meet the world food demand. Biological control offers a suitable substitute towards chemical pesticides which have their drastic effects on both man and environment. Several lytic enzymes play a key role in these alternative strategies on control of pathogens and pests. Chitinase is one such enzyme complex that has been effectively used in biological control. These enzymes breakdown chitin efficiently into N-acetylglucosamine and its oligomers called chitooligosac-charides. Chitin forms the exoskeleton of arthropods, nematodes and cell wall component in fungi. Due to this, chitin has been targeted for the development of biological control agents against plant pathogens. Plants have known to implicate chitinases in defence against plant pathogens thus chitinases provide an alternate solution to harmful chemicals to combat plant pathogens. This review throws light on the current status of agriculture and further deals with chitinases native to many plants and genetically modified ones, which have been designed in defence against many plant pathogens.