The HyPRP gene EARLI1 has an auxiliary role for germinability and early seedling development under low temperature and salt stress conditions (presentation)
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. Comparisons of control, overexpressing (OX), and knockout (KO) lines indicated that higher than wild type levels of EARLI1 improved germinability, root elongation, fresh weight accumulation, and reduction of sodium accumulation in leaves under salt stress, as well as germinability under low-temperature stress. Abscisic acid (ABA) contents remained relatively low under 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 KIN1, P5SC1, 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.