Role of Phosphatidic Acid in High Temperature Tolerance in Maize
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Maize (Zea mays L.) germplasm exhibits large genetic variations in tolerance to high temperature (HT) stress under field conditions, but the mechanisms underling this variation are largely unknown. Based on many years of field observation, maize inbred line B76 consistently displays better tolerance to HT than B106. Heat waves during growing season cause leaf firing in developing leaves and tassel blasting in B106 but not in B76. The difference in HT tolerance between the two inbred lines was confirmed in growth chambers under controlled conditions. The two inbred lines showed similar level in the induction of heat shock proteins and a maize chloroplast protein synthesis elongation factor (EF-Tu), two mechanisms known to involve in HT tolerance in maize. A drastic decrease in photosynthetic system II (PSII) quantum efficiency occurred at 34 to 35C in B106; in B76, it occurred at a much higher temperature (>38C). Cell membranes of B76 appeared to be more stable under HT than those of B106 based on electrolyte leakage analysis. Lipid profiles of young developing leaves by lipidomics showed that, among all lipids detected, only phosphatidic acid (PA) exhibited Significant higher level in B76 than in B106 under both normal and HT stressed conditions (p < 0.02). Moreover, PA was the only lipid that was significantly increased by HT treatment (p < 0.05). Our results suggest that membrane thermostability is essential to HT tolerance and that PA may play an important role in imparting membrane thermostability, and, hence, HT tolerance in maize. Crop Science Society of America.
author list (cited authors)
Chen, J., Xu, W., Burke, J. J., & Xin, Z.
complete list of authors
Chen, Junping||Xu, Wenwei||Burke, John J||Xin, Zhanguo