Identification, cloning and characterization of AcMSH1 from Onion (Allium cepa L.).

BACKGROUND: MSH1 (MutS homolog1) is a nuclear-encoded protein that plays a crucial role in maintaining low mutation rates and stability of the organellar genome. While plastid MSH1 maintains nuclear epigenome plasticity and affects plant development patterns, mitochondrial MSH1 suppresses illegitimate recombination within the mitochondrial genome, affects mitochondrial genome substoichiometric shifting activity and induces cytoplasmic male sterility (CMS) in crops. However, a detailed functional investigation of onion MSH1 has yet to be achieved. MATERIALS AND RESULTS: The homology analysis of onion genome database identified a single copy of the AcMSH1 gene in the onion cv. Bhima Super. In silico analysis of AcMSH1 protein sequence revealed the presence of 6 conserved functional domains including a unique MSH1-specific GIY-YIG endonuclease domain at the C-terminal end. At N-terminal end, it has signal peptide sequences targeting chloroplast and mitochondria. The concentration of AcMSH1 was found to be highest in isolated mitochondria, followed by chloroplasts, and negligible in the cytoplasmic fraction; which proved its localization to the mitochondria and chloroplasts. Quantitative expression analysis revealed that AcMSH1 protein levels were highest in leaves, followed by flower buds, root tips, flowers, and umbels, with the lowest amount found in callus tissue. CONCLUSION: Onion genome has single copy of MSH1, with characteristic GIY-YIG endonuclease domain. AcMSH1 targeted towards both chloroplasts and mitochondria. The identification and characterisation of AcMSH1 may provide valuable insights into the development of CMS lines in onion.

MSAP Marker Based Epigenetic Regulation in Symptomatic and Asymptomatic Floral Malady of Soybean (Glycine max)

Abstract: It has learned that soybean is being affected by a floral disorder known as floral malady where plants fail to develop pod and do notattendfull maturity. For this floral disorder, we present a new methylation-sensitive amplified polymorphism (MSAP) approach for the evaluation of relative quantitative characteristics of non-methylation, hyper-methylation, hemi-methylation, and full methylation status of CCGG sequences, which are recognized by the isoschizomers HpaII and MspI. We applied a technique to analyze alterations in the cytosine methylation a popular Indian soybean (Glycine max L.) genotype, JS-335.The result revealed that in the symptomatic plant, out of 392 MSAP sites, 281 (71.68%), 33 (8.41%),38 (9.69%), and 40(10.20%) found to beun-methylated, hemi-methylated, fully methylated and hyper-methylated, respectively. Whereas, the MSAP profile of asymptomatic plants revealedout of 402MSAP sites, 330 (81.28%) was un-methylated, 22(5.41%) hemi-methylated,29(7.14%) fully methylatedand 25 (6.15%) hypermethylated. In comparison with asymptomatic(18.71%) plant, approximately 10% increased methylation was noted in symptomatic(28.31%) plantprofiles. The increased levels of methylation was recorded in the symptomatic plants about 28.31%and18.71% in asymptomatic. The study showed a higher epigenetic influence on JS-335 genotype of floral malady symptomatic than same genotype of asymptomatic plant. No pod formation in symptomatic plant induce genome wide changes either in promoter or coding region of gene(s) and DNA fragments showing polymorphism related to differences in pattern and extent of methylation associated with floral malady.