Analysis of biochemical variations and microRNA expression in wild (Ipomoea campanulata) and cultivated (Jacquemontia pentantha) species exposed to in vivo water stress

The current study analyses few important biochemical parameters and microRNA expression in two closely related species (wild but tolerant Ipomoea campanulata L. and cultivated but sensitive Jacquemontia pentantha Jacq.G.Don) exposed to water deficit conditions naturally occurring in the field. Under soil water deficit, both the species showed reduction in their leaf area and SLA as compared to well-watered condition. A greater decrease in chlorophyll was noticed in J. pentantha (similar to 50 %) as compared to I. campanulata (20 %) under stress. By contrast, anthocyanin and MDA accumulation was greater in J. pentantha as compared to I. campanulata. Multiple isoforms of superoxide dismutases (SODs) with differing activities were observed under stress in these two plant species. CuZnSOD isoforms showed comparatively higher induction (similar to 10-40 %) in I. campanulata than J. pentantha. MicroRNAs, miR398, miR319, miR395 miR172, and miR408 showed opposing expression under water deficit in these two plant species. Expression of miR156, miR168, miR171, miR172, miR393, miR319, miR396, miR397 and miR408 from either I. campanulata or J. pentantha or both demonstrated opposite pattern of expression to that of drought stressed Arabidopsis. The better tolerance of the wild species (I. campanulata) to water deficit could be attributed to lesser variations in chlorophyll and anthocyanin levels; and relatively higher levels of SODs than J. pentantha. miRNA expression was different in I. campanulata than J. pentantha.