Isolation and drought-tolerant function analysis of ZmPti1-1, a homologue to Pti1, from maize (Zea mays L.)
Pto-interacting 1(Pti1) has been well established to play important roles in plant disease and salt response, but its potential roles in the response to drought stress is unknown. In this study, the Pti1- like gene named as ZmPti1-1 was cloned from maize, sequence analysis showed that ZmPti1-1 encodes a polypeptide of 363 amino acids with predicted molecular mass of 39.0 kDa and an isoelectric point of 8.14. ZmPt1-1 is dramatically induced by abscisic acid (ABA) and mannitol (data not shown). In order to analyze the further drought tolerant functions, ZmPti1-1 was over-expressed in Arabidopsis. Under drought stress, compared with wild type, survival rate of the three transgenic lines, which was 70, 76 and 87%, respectively, was significantly higher than that of wild type which was 29%; there were lower water loss, lower cell membrane damage, higher relative water content, higher total soluble sugars, higher proline content and higher yield for transgenic plants. Based on the present knowledge, this is the first report that over-expression of Pti1-like gene improved drought tolerance in plants.
Key words: ZmPti1-1, transgenic Arabidopsis, drought tolerance.