Protein identification and expression regulation mechanism of heterotypic leaves formation in Populus euphratica Oliv.

Abstract

Populus euphratica Oliv. is a typical desert plant. The heteromorphic leaves of P. euphratica at different growth stages is a crucial apparent characteristic of P. euphratica, which can help itself adapt to the harsh growth environment. In this study, four-leaf shapes young leaves of P. euphratica were used as materials. 2-DE (two-dimensional electrophoresis) was used to screen and identify four critical proteins related to heteromorphic leaf formation from poplar and P. euphratica protein databases based on leaf shape index change. It was found that ATP synthase and HSP 70 were consistent with their mRNA expression levels, while OEE1 and Rubisco activatase were negatively correlated with their mRNA expression levels. Based on our experimental results and bioinformatics analysis, it is speculated that ATP synthase can change the morphology of cells by promoting the vertical growth of cells and then cause changes in leaf traits; HSP 70 affected by ABA affects the occurrence of heteromorphic leaves by regulating programmed cell death; OEE1 content increases gradually with the increase of leaf area to cope with environmental changes such as light and salt stress; however, the expression of OEE1 mRNA was opposite, which indicated that there might be some post-transcriptional regulation mode which promoted the accumulation of OEE1. By identifying proteins related to the occurrence of heteromorphic leaves of P. euphratica and transcriptome correlation analysis, the protein and mRNA levels were preliminarily studied, which provided a new theoretical basis for the molecular mechanism of heteromorphic leaves of P. euphratica.