The Arabidopsis F-box protein FOF2 regulates ABA-mediated seed germination and drought tolerance. (December 2020)

• Record Type: Journal Article
• Authors: Qu, Lina; Sun, Mengsi; Li, Xinmei; He, Reqing; Zhong, Ming; Luo, Dan; Liu, Xuanming; Zhao, Xiaoying
• Is Part Of: Plant science. Volume 301(2020)
• Publication Date: 2020-12
• Subjects: F-box of flowering 2 (FOF2) -- Abscisic acid (ABA) -- ABA-Insensitive 3 (ABI3) -- ABA-Insensitive 5 (ABI5) -- Drought tolerance -- NCED3; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2020.110643
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: FOF2 is induced by ABA and drought stress in an ABA-dependent manner. FOF2 inhibits ABA-mediated seed germination partially by repressing ABI3 and ABI5. Overexpression of FOF2 enhances plant drought tolerance. FOF2 promotes ABA-induced stomatal closure and ABA biosynthesis under drought stress. Abstract: The phytohormone abscisic acid (ABA) plays a crucial role at various plant developmental stages, including seed germination and seedling development, and regulates stomatal aperture in response to drought. However, the underlying mechanisms are not well understood. Here, we showed that F-BOX OF FLOWERING 2 ( FOF2 ) is induced by ABA and drought stress. Overexpression of FOF2 led to reduced ABA sensitivity during seed germination and early seedling development, whereas the fof2 mutant exhibited increased sensitivity to ABA. Molecular and genetic analyses revealed that FOF2 negatively affected ABA-mediated seed germination and early seedling development partially by repressing the expression of the ABA-signaling genes ABI3 and ABI5 . Additionally, we found that FOF2 -overexpressing plants exhibited increased ABA contents, enhanced ABA sensitivity during stomatal closure, and decreased water loss, thereby improving tolerance to drought stress, in contrast to the fof2 mutant. Consistent with a higher ABA content and enhanced drought tolerance, the expression of ABA- and drought-induced genes and the ABA-biosynthesis gene NCED3 was upregulated in the FOF2 -overexpressing plants but downregulated in fof2 mutant in response to drought stress. Taken together, our findings revealed that FOF2 plays an important negative role in ABA-mediated seed germination and early seedling development, as well as a positive role in ABA-mediated drought tolerance.