Emerging Models: MicroRNAs in jute
Jute (Corchorus spp.) is an important fibre crop in South Asia. This smallholder’s crop is vulnerable to a most devastating pathogen, Macrphomina phaseolina. It causes damping off, root rot and collar rot collectively known as stem rot, which results in up to 30% yield loss and low fibre quality. The pathogen first causes root rot under high soil temperature and low soil moisture (drought) conditions and then colonises physiologically altered stem causing stem rot at maturity, under favourable weather conditions. However, the molecular mechanisms underlying are unknown. Plant-pathogen-weather interface is regulated by a number of genes. Existing, probe-dependent gene regulation analysis methods require plant and pathogen cells to be physically separated. However, probe-independent RNA sequencing method allows plant and pathogen transcripts to be analysed simultaneously.
MicroRNA effectors serves the conserved gene regulatory mechanisms which also have been reported to control plant-pathogen interactions. Most works on miRNAs have focused on initial pathogen infection processes at early growth stages of plants, under controlled environment. However, miRNA-mediated regulation of disease development throughout the life cycle of plants under the influence of abiotic stresses, such as drought has not been studied so far. Since, stem rot becomes severe at maturity under hot and humid weather conditions, despite the colonisation of roots by M. phaseolina at early growth stages of jute under drought conditions, Lalit Kharbikar, a scientist at Central Research Institute for Jute and Allied Fibres, India believes that the jute-M. phaseolina-weather interaction could provide a good model system to study whether the physiological alterations induced by pathogen colonisation or abiotic stresses, facilitate the development of diseases in plants. Characterisation of miRNAs involved in this interaction could help elucidate the molecular interactions between plant biotic and abiotic stresses, he says.