Identifying oxidative stress responsive genes in chickpea (Cicer arietinum)
Chickpea (Cicer arietinum) is the second most important food legume globally, with 11.62 million tonnes yielded annually. However, it is anticipated that to meet global food demand, annual production must increase to 17 million by 2020. Chickpea production is currently limited because of its sensitivity to abiotic stresses. Under environmental stress, oxidative stress due to over production of Reactive Oxygen Species (ROS) causes cellular damage, reducing plant productivity through impairing photosynthetic carbon gain and leaf growth rate. This highlights the need to improve crop tolerance under these conditions, through identification of biomarkers for molecular breeding and genetic manipulation. A bioinformatics approach with a focus on potential antioxidant genes was undertaken to identify oxidative stress responsive genes in chickpea, as well as gene orthologs from soybean (Glycine max) and Medicago trancatula. It was found that genes encoding late embryogenesis abundant (LEA) proteins, peroxiredoxins (Prx), uncoupling proteins (UCPs) and a potential UPOX protein, as well as proteins involved in synthesis of proline, galactinol, and glutathione, were highly up-regulated under oxidative stress. To verify these responses, 21-day-old chickpeas (cv. Rupali) were subjected to each of three environmental stressors: salinity, drought and paraquat, with tissue samples collected at various time points for growth rate analysis, malondialdehyde measurements and expression analysis. The gene expression response to oxidative stress was quantified using qRT-PCR for both root and leaf tissue, identifying a cassette of oxidative stress responsive genes for potential use as biomarkers in chickpea.