The HyPRP gene EARLI1 has an auxiliary role for germinability and early seedling development under low temperature and salt stress conditions in Arabidopsis thaliana. Planta

Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Life Science, Northwest University, Xi'an 710069, Shaanxi, China.
Planta (Impact Factor: 3.26). 05/2011; 234(3):565-77. DOI: 10.1007/s00425-011-1425-9
Source: PubMed


The effect of the hybrid proline-rich protein (HyPRP) gene EARLI1 on the rate of germination (germinability) of Arabidopsis seeds and seedling growth under low temperature and salt stress conditions was investigated. EARLI1 was induced during germination in embryonic tissues, and was strongly expressed in certain parts of young seedlings. Comparisons of control, overexpressing (OX), and knockout (KO) lines indicated that higher than wild type levels of EARLI1 improved germinability, root elongation, and reduction of sodium accumulation in leaves under salt stress, as well as germinability under low-temperature stress. Abscisic acid (ABA) contents were relatively low after prolonged salt stress, suggesting that EARLI1 has an ABA-independent effect on germinability under these conditions. Overexpression of EARLI1 during germination enhanced the sensitivity of seeds to exogenously applied ABA, suggesting that EARLI1 has an ABA-dependent negative effect on seed germinability under high ABA stress conditions. Well-known stress response marker genes such as COR15a, KIN1, P5SC1, and RD29 were unaffected whereas P5SC2, RD22, or RAB18 were only slightly affected in OX and KO plants. The pleiotropic effects of EARLI1 during stress and an absence of strong regulatory effects on stress marker genes suggest that this HyPRP gene has an auxiliary role for various stress protection responses in Arabidopsis.

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    • "Apparently, neither AZI1 nor EARLI1 deficiency can be fully compensated for by other members of the EARLI or LTP family. Similarly to EARLI1 overexpression (Xu et al., 2011a), elevated AZI1 levels improve salt tolerance. Consequently, hypersensitivity in the mutants is not merely due to an imbalance in the relative amounts of EARLI-type HyPRPs. "
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    • "Although huge progress has been made in understanding the molecular mechanisms underlying HyPRP action in several plants (Deutch and Winicov, 1995; Richards and Gardner, 1995; Goodwin et al., 1996; Josè-Estanyol and Puigdomènech, 1998; Wilkosz and Schläppi, 2000; Bubier and Schläppi, 2004; Zhang and Schläppi, 2007; Priyanka et al., 2010; Dvoráková et al., 2011; Huang et al., 2011; Xu et al., 2011), the roles of the soybean HyPRP gene family still remain largely unknown. The sequencing and assembly of the soybean genome (Schmutz et al., 2010) may provide new approaches for identifying protein-coding loci possibly involved in the ability of soybean to survive stressful conditions. "
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