Systematic analysis and functional verification of sugarcane PYL gene family reveals that ScPYL61-ScPP2C49-ScSnRK2s module contributes to drought resistance

Abstract

The core of the ABA signaling pathway consists of Pyrabactin Resistance 1-Like (PYL), group A PP2C, and SnRK2 gene family, which play crucial roles in various environmental stress responses of plants. The PYL proteins, as ABA receptors, are involved in the initial step of ABA signal transduction. However, systematic analysis of the PYL gene family in sugarcane have not been reported. In this study, 63 ScPYL genes from Saccharum spp. cultivar ZZ1 were identified, which exhibited a non-uniform distribution on 36 chromosomes. Phylogenetic analysis indicated that ScPYL members were divided into three groups, in which the ABREs were universally presented in the promoters of most ScPYL genes. The transcription levels of ScPYL61 were significantly upregulated by PEG and ABA. The overexpression of ScPYL61 enhanced drought tolerance of plant through reducing water loss and promoting stomatal closure. Further study revealed that the overexpression of ScPYL61 in Arabidopsis significantly increased the ABA sensitivity and activated ABA signaling. Moreover, ScPYL61 could interact with ScPP2C49 and the interaction was promoted by ABA. In addition, ScPP2C49 interacts with a series of ScSnRK2s, including ScSnRK2.2/3/6/7, which possibly formed the ScPYL61-ScPP2C49-ScSnRK2s module to mediate ABA signaling and participate in drought stress response. Taken together, our findings identified a new PYL-PP2C-SnRK2 molecular module in sugarcane and provided useful insights into the molecular functions of ScPYL61 gene responding to ABA and drought stress.