A Novel Dominant Allele from 93-11, ES(4), Represses Reactive Oxygen Species Scavenging and Leads to Early-Senescence in Rice

Abstract

Senescence is the last developmental process in plant, which has an important impact on crop yield and quality. In this study, a stable hereditary early-senescence line BC64 was isolated from the high-generation recombinant inbred lines of 93-11 and Wuyunjing7 (W7). Genetic analysis showed that the premature aging phenotype was controlled by a dominant gene derived from 93-11. By linkage analysis, the gene was primarily mapped in the region between marker B4 and B5 near the centromere of chromosome 4, described as ES(4). Through multiple backcrossing with W7, the near-isogenic line of ES(4) (NIL-ES(4)) was obtained. Compared with wild-type W7, NIL-ES(4) plants showed more sever senescence phenotype in both nature and dark conditions. In NIL plants, leaves turned yellow at the fully tillering stage; photosynthetic rate, pollen fertility and seed setting rate were decreased. Moreover, the malondialdehyde, proline content and relative conductivity in NIL-ES(4) were significantly higher than those in W7; both transcript level and activities of reactive oxygen species scavenging enzymes were repressed; H2O2 and O2− were significantly accumulated. This study provides a basis for further cloning and function identification of ES(4).