Nei 6 You 7075, a hybrid rice cultivar, exhibits enhanced disease resistance and drought tolerance traits

Abstract

Background: Rice is the main food crop for much of the population in China. Therefore, selecting and breeding new disease resistance and drought tolerance in rice is essential to ensure national food security. The utilization of heterosis has significantly enhanced rice productivity, yet many of the molecular mechanisms underlying this phenomenon remain largely unexplored. 'Nei 6 You 7075' ('N6Y7075') is a novel hybrid rice cultivar with exceptional quality, developed through the crossbreeding of 'Fuhui 7075' ('FH7075') and 'Neixiang 6 A' ('NX6A'). However, the precise mechanisms underlying the disease resistance and drought tolerance in 'N6Y7075' are poorly understood. In this study, we investigated the resistance of hybrid rice 'N6Y7075' to bacterial blight (Xanthomonas oryzae pv. oryzae), rice blast (Magnaporthe oryzae), and drought and identified differentially expressed genes between hybrid rice 'N6Y7075' and its parents through RNA-seq analysis.

Results: Our research found that the hybrid 'N6Y7075' and its female parent 'NX6A' were less susceptible to bacterial blight and rice blast than the male parent 'FH7075', while 'FH7075' showed better drought tolerance than 'NX6A'. The hybrid 'N6Y7075' exhibited heterosis. Clustering results revealed that the expression profiles of the F1 hybrid closely resembled those of its parental lines rather than exhibiting an intermediate profile between the two parental lines. The disease resistance of hybrid rice 'N6Y7075' may be attributed to the plant-pathogen interaction pathways involving Xa21, CDPK, and RPM1-mediated hypersensitive response and WRKY1-induced defense-related gene expression and programmed cell death. The MAPK signaling pathway PR1 could also be associated with plant defense responses. Hybrid rice 'N6Y7075' may enhance drought tolerance by regulating MAPKKK17 and WAK60 in the MAPK signaling pathway. These proteins affect ABA stress adaptation and stomatal development in plants, respectively.

Conclusions: Our results provide a preliminary exploration of 'N6Y7075' disease resistance and drought tolerance and provide a relevant theoretical basis for its further study and use. This study provides insights into the molecular mechanisms of heterosis in hybrid rice and identifies potential associated genes.

Keywords: Bacterial blight; Drought tolerance; Heterosis; Hybrid rice; Rice blast; Transcriptome.