Tanwy Dasmandal

Leguminous crops are important crops next to cereals. The production and productivity of these crops has a major impact on country’s economy as well as the economic status of the stakeholders farmers. Moreover, the nutritional security can be ensured through growing of these leguminous crops. In this context, two leguminous crops, chickpea and soybean along with their transcriptome data were considered in the present study. With the advent of NGS technologies it has become feasible to unravel the underlying complex mechanisms at genome level. Even though the coding genes play a major role in various abiotic and biotic stress mechanisms, there are several noncoding RNAs which regulate the genes responsible for stress tolerance mechanisms. However, the identification and characterization of circular RNAs, a type of non-coding RNAs as well as the circRNA-miRNA-mRNA networks in legumes has not been fully explored. Hence, the present study on ‘Identification and characterization of circular RNAs in legumes’ has been taken up with the objectives: (i) to identify and characterize circRNAs responsible for biotic and abiotic stress tolerance in the leguminous crops and (ii) to study the relationship between circRNA-miRNAmRNA. Here the transcriptome data of the said crops were collected from public domain (NCBI, Ensemble, etc) and the algorithm given in CIRI (CircRNA Identifier) was used to identify the circRNAs under drought (abiotic) and wilt (biotic) stress conditions. The characterization of circRNAs was done through their differential expression in both drought and wilt stress conditions. The differentially expressed (DE) circRNAs were further probed for their role in circRNA-miRNAmRNA interaction. Finally, the identified genes from the network were studied for their functionality in stress tolerance mechanisms. The results revealed identification of 200 and 285 circRNAs under control and drought stress conditions in chickpea, 57 and 66 circRNAs under control and drought stress conditions in soybean and 48 and 75 circRNAs under control and wilt stress conditions in soybean. The number of DEcircRNAs were 44, 23 and 24 in chickpea-drought, soybean-drought and soybean-wilt respectively. These DEcircRNAs were found to act as sponges for 40 (chickpea-drought), 17 (soybean-drought) and 10 (soybean-wilt) miRNAs. Besides, these miRNAs were found to target 145 (chickpea-drought), 281 (soybean-drought) and 275 (soybeanwilt) mRNAs. GO study was carried out for the mRNAs and found that they are involved in biological processes like ‘metabolic process’ and ‘cellular process’, molecular functions like ‘binding’ and ‘catalytic activities’ and cellular components like ‘cell’, ‘cell part’ and ‘membrane part’. Thus circRNA-miRNA-mRNA network play a vital role in stress responsive mechanisms through their activities in hormone signal transduction, response to stress, response to auxin and transcription factor activity.