Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
Int J Mol Sci. 2022 May 16;23(10):5537. doi: 10.3390/ijms23105537.
Abscisic acid (ABA) and gibberellic acid (GA) antagonistically regulate many aspects of plant growth, including seed dormancy and germination. The effects of these hormones are mediated by a complex network of positive and negative regulators of transcription. The DELLA family of proteins repress GA response, and can promote an ABA response via interactions with numerous regulators, including the ABA-insensitive (ABI) transcription factors. The AFP family of ABI5 binding proteins are repressors of the ABA response. This study tested the hypothesis that the AFPs also interact antagonistically with DELLA proteins. Members of these protein families interacted weakly in yeast two-hybrid and bimolecular fluorescence complementation studies. Overexpression of AFPs in , a mutant that over-accumulates DELLA proteins, suppressed DELLA-induced overaccumulation of storage proteins, hyperdormancy and hypersensitivity to ABA, but did not alter the dwarf phenotype of the mutant. The interaction appeared to reflect additive effects of the AFPs and DELLAs, consistent with action in convergent pathways.
脱落酸（ABA）和赤霉素（GA）拮抗调节植物生长的许多方面，包括种子休眠和萌发。这些激素的作用是通过转录的正和负调节剂的复杂网络介导的。DELLA 家族的蛋白质抑制 GA 反应，并能通过与许多调节剂相互作用促进 ABA 反应，包括非敏感的 ABI（ABI）转录因子。AFP 家族的 ABI5 结合蛋白是 ABA 反应的抑制剂。本研究检验了 AFP 也与 DELLA 蛋白相互拮抗的假设。这些蛋白质家族的成员在酵母双杂交和双分子荧光互补研究中相互作用较弱。在 ，一个过度积累 DELLA 蛋白的突变体中过表达 AFP，抑制了 DELLA 诱导的储存蛋白过度积累、超休眠和对 ABA 的敏感性，但没有改变突变体的矮化表型。这种相互作用似乎反映了 AFP 和 DELLA 的加性效应，与趋同途径的作用一致。
