ibclogo XVI International Botanical Congess


Abstract Number: 3860
Session = 15.15.6


EXPANSINS AND ADAPTATION OF MAIZE ROOTS TO WATER STRESS


Yajun Wu and Daniel J. Cosgrove, Penn State University


Growing plants possess many mechanisms for adapting to mild water deficits. Previous work suggested that expansins might be involved in maintenance of cell elongation in drought-stressed maize primary roots (Plant Physiol 111:765). Expansins are wall-loosening proteins thought to be key regulators of wall yielding properties (Plant Physiol 118:333). We have identified maize cDNAs for 14 distinct expansin genes: 6 alpha-expansins and 8 beta-expansins. Five of these expansins are expressed in roots, but none are completely specific to roots. Preliminary results indicate that water stress leads to selective increase in RNA transcripts for one a-expansin and one b-expansin. These results support the hypothesis that drought enhances expression of a subset of the expansin gene family, thereby enabling roots to continue to grow despite low turgor pressure.


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