Overexpression of a Zea mays phospholipase C1 gene enhances drought tolerance in tobacco in part by maintaining stability in the membrane lipid composition

摘要

Phosphatidylinositol-specific phospholipase C (PI-PLC: EC 3.1.4.11) plays key roles in a variety of physiological processes in plants. We previously reported that the putative PLC genes from maize (Zea mays L.) are transcriptionally upregulated in response to drought (Sui et al. in Gene 426:47–56, 2008). In this paper, we report the further characterization of ZmPLC1. First, the expression of ZmPLC1 successfully complemented the yeast plc1 mutant BY4742 and restored its growth defects with regard to galactose utilization. The determination of PLC activity in the transformed yeast strain further demonstrated the enzymatic properties of ZmPLC1. Second, we obtained drought stress-tolerant transgenic tobacco plants by overexpressing the maize PLC1 gene under the control of the CaMV 35S promoter. To determine whether ZmPLC1 regulates plants’ response to drought stress by regulating phospholipid and galactolipid levels, we analyzed the lipid species in ZmPLC1 transgenic and wild-type tobacco plants before and after drought treatment using an ESI–MS/MS approach. The results show that, under drought stress conditions, the overexpression of ZmPLC1 in tobacco maintained the stability of the unsaturated lipid species PtdIns, MGDG, DGDG, PE, and PC in leaves, whereas their levels in wild-type tobacco decreased dramatically. These results not only demonstrate the conserved function of ZmPLC1 and its practical applications in dicots, but also elucidate the molecular mechanism of the role PI-PLC plays in plant responses to drought stress.