The SUPPRESSOR of MAX2 1 (SMAX1)-Like SMXL6, SMXL7 and SMXL8 Act as Negative Regulators in Response to Drought Stress in Arabidopsis

• DOI: 10.1093/pcp/pcaa066
• Publication Date: 2020-05-02T11:08:28Z
• Authors: Tao Yang; Yuke Lian; Jihong Kang; Zhiyuan Bian; Lijuan Xuan; Zhensheng Gao; Xinyu Wang; Jianming Deng; Chongying Wang
• Keywords: Strigolactone; Drought Tolerance; Crosstalk; Wild type

Abstract Drought represents a major threat to crop growth and yields. Strigolactones (SLs) contribute regulating shoot branching by targeting the SUPPRESSOR OF MORE AXILLARY GROWTH2 (MAX2)-LIKE6 (SMXL6), SMXL7 SMXL8 for degradation in MAX2-dependent manner Arabidopsis. Although SLs are implicated plant drought response, functions of SMXL6, 7 8 SL-regulated response stress have remained unclear. Here, we performed transcriptomic, physiological biochemical analyses smxl6, 7, max2 plants understand basis SMXL6/7/8-regulated response. We found that three D53 (DWARF53)-Like SMXL members, 8, involved as smxl6smxl7smxl8 triple mutants showed markedly enhanced tolerance compared wild type (WT). The exhibited decreased leaf stomatal index, cuticular permeability water loss, increased anthocyanin biosynthesis during dehydration. Moreover, were hypersensitive ABA-induced closure ABA responsiveness after germination. In addition, RNA-sequencing analysis leaves D53-like smxl mutants, SL-response mutant WT under normal dehydration conditions revealed an SMXL6/7/8-mediated network controlling adaptation via many stress- and/or ABA-responsive SL-related genes. These data further provide evidence crosstalk between ABA- SL-dependent signaling pathways responses drought. Our results demonstrate vital components SL negatively responses, suggesting genetic manipulation SMXL6/7/8-dependent may novel ways improve resistance.