Giving drought the cold shoulder: a relationship between drought tolerance and fall dormancy in an agriculturally important crop

Pembleton, Keith G. and Sathish, Puthigae (2014) Giving drought the cold shoulder: a relationship between drought tolerance and fall dormancy in an agriculturally important crop. AOB Plants, 6 (plu012). pp. 1-17. ISSN 2041-2851

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The growth of fall dormant/freezing tolerant plants often surpasses the growth of non-fall dormant/non-freezing tolerant types of the same species under water-limited conditions, while under irrigated conditions non-fall dormant types exhibit superior yield performance. To investigate the mechanism behind this phenomenon, we exposed seven diverse alfalfa (Medicago sativa) cultivars to water-limited and fully watered conditions and measured their shoot growth, shoot water potential and gas exchange parameters and the relative abundance of taproot RNA transcripts associated with chilling stress/freezing tolerance. Fall dormant cultivars had greater shoot growth relative to the fully watered controls under a mild water deficit (a cumulative water deficit of 625 mL pot−1) and did not close their stomata until lower shoot water potentials compared with the more non-fall dormant cultivars. Several gene transcripts previously associated with freezing tolerance increased in abundance when plants were exposed to a mild water deficit. Two transcripts, corF (encodes galactinol synthase) and cas18 (encodes a dehydrin-like protein), increased in abundance in fall dormant cultivars only. Once water deficit stress became severe (a cumulative water deficit of 2530 mL pot−1), the difference between fall dormancy groups disappeared with the exception of the expression of a type 1 sucrose synthase gene, which decreased in fall dormant cultivars. The specific adaptation of fall dormant cultivars to mild water deficit conditions and the increase in abundance of specific genes typically associated with freezing tolerance in these cultivars is further evidence of a link between freezing tolerance/fall dormancy and adaption to drought conditions in this species.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Open Access Journal- Published source must be acknowledged.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 28 Jul 2016 06:21
Last Modified: 04 Jun 2018 06:13
Uncontrolled Keywords: alfalfa; forage legumes; gene expression; lucerne moisture stress
Fields of Research : 06 Biological Sciences > 0607 Plant Biology > 060799 Plant Biology not elsewhere classified
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Identification Number or DOI: 10.1093/aobpla/plu012

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