Identification of drought tolerant mechanisms in a drought-tolerant maize mutant based on physiological, biochemical and transcriptomic analyses

• DOI: 10.1186/s12870-020-02526-w
• Publication Date: 2020-07-03T06:14:56Z
• Authors: Qinbin Zhang; Hui Liu; Xiaolin Wu; Wei Wang
• Keywords: 2. Zero hunger; 0301 basic medicine; Drought stress; Gene Expression Profiling; Botany; Drought-tolerant mutant; 15. Life on land; Real-Time Polymerase Chain Reaction; Transcriptomic analysis; Adaptation, Physiological; Zea mays; 6. Clean water; Droughts; 03 medical and health sciences; Cell Wall; Stress, Physiological; QK1-989; Mutation; Differentially expressed genes; Drought-adaptation model; RNA-Seq; Sugars; Research Article

Abstract Background Frequently occurring drought stress negatively affects the production of maize worldwide. Numerous efforts have been made to develop drought-tolerant maize lines and to explore drought tolerant mechanisms in maize. However, there is a lack of comparative studies on transcriptomic changes between drought-tolerant and control maize lines.

Results In the present study, we have developed a drought-tolerant maize mutant (C7–2t) by irradiating the seeds of maize inbred line ChangC7–2 (C7–2) with 60Co-γ. Compared to its wild type C7–2, C7–2t exhibited a significantly delayed wilting and higher drought tolerance under both the controlled and field conditions, indicating its high water-holding ability. Transcriptomic profiling was performed to identify differentially expressed genes (DEGs) between C7–2 and C7–2t during drought. As a result, a total of 4552 DEGs were implied in drought tolerance of C7-2 and C7-2t. In particular, the expression of photosynthesis-related genes in C7–2 was inhibited, whereas these genes in C7–2t were almost unaffected under drought. Moreover, a specific set of the DEGs were involved in phenylpropanoid biosynthesis and taurine (hypotaurine) metabolism in C7–2t; these DEGs were enriched in cell components associated with membrane systems and cell wall biosynthesis.

Conclusions The drought tolerance of C7–2t was largely due to its high water-holding ability, stable photosynthesis (for supporting osmoregulation) and strengthened biosynthesis of cell walls under drought conditions.