ABSTRACT
MAIN CONCLUSION: The study evaluates the potential of Spray-Induced Gene Silencing and Host-Induced Gene Silencing for sustainable crop protection against the broad-spectrum necrotrophic fungus Sclerotinia sclerotiorum. Sclerotinia sclerotiorum (Lib.) de Bary, an aggressive ascomycete fungus causes white rot or cottony rot on a broad range of crops including Brassica juncea. The lack of sustainable control measures has necessitated biotechnological interventions such as RNA interference (RNAi) for effective pathogen control. Here we adopted two RNAi-based strategies-Spray-Induced Gene Silencing (SIGS) and Host-Induced Gene Silencing (HIGS) to control S. sclerotiorum. SIGS was successful in controlling white rot on Nicotiana benthamiana and B. juncea by targeting SsPac1, a pH-responsive transcription factor and SsSmk1, a MAP kinase involved in fungal development and pathogenesis. Topical application of dsRNA targeting SsPac1 and SsSmk1 delayed infection initiation and progression on B. juncea. Further, altered hyphal morphology and reduced radial growth were also observed following dsRNA application. We also explored the impact of stable dsRNA expression in A. thaliana against S. sclerotiorum. In this report, we highlight the utility of RNAi as a biofungicide and a tool for preliminary functional genomics.
Subject(s)
Ascomycota , Nicotiana , Plant Diseases , RNA Interference , Ascomycota/physiology , Ascomycota/genetics , Plant Diseases/microbiology , Plant Diseases/prevention & control , Nicotiana/genetics , Nicotiana/microbiology , Mustard Plant/genetics , Mustard Plant/microbiology , Fungal Proteins/genetics , Fungal Proteins/metabolism , Arabidopsis/genetics , Arabidopsis/microbiology , Transcription Factors/genetics , Transcription Factors/metabolism , RNA, Double-Stranded/geneticsABSTRACT
BACKGROUND: Single nucleotide substitutions (SNS) in genetic codon are of prime importance due to their ability to alter an amino acid sequence as a result. Given the nature of genetic code, any SNS is expected to change the protein sequence randomly into any of the 64 possible codons. In this paper, we present a theoretical analysis of how single nucleotide substitutions in genetic codon may affect resulting amino acid residue and what is the most likely amino acid that will get selected as a result. METHODS: A probability matrix was developed showing possible changes and routes likely being followed as a result of base substitution mutation causing changes at the translational level for the amino acid being encoded. RESULTS: We observe that in event of single base pair substitution in a given amino acid; a chosen set of amino acids is theoretically more probable to be resulted suggesting a directional rather than a random change. This study also indicates that for a given amino acid coded by a number of synonymous codons, all synonymous codons will result into same list of amino acids in case of all possible SNS at three positions. CONCLUSION: The present work has resulted into development of a theoretical probability matrix which can be used to predict changes in amino acid residues in a protein sequence caused by single base substitutions.
