Arabidopsis Transcription Factors SPL1 and SPL12 Confer Plant Thermotolerance at Reproductive Stage

• Published in: Molecular plant Vol. 10; no. 5; pp. 735 - 748
• Main Authors: Chao, Lu-Men, Liu, Yao-Qian, Chen, Dian-Yang, Xue, Xue-Yi, Mao, Ying-Bo, Chen, Xiao-Ya
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.05.2017
• Subjects: abscisic acid; Abscisic Acid - metabolism; Arabidopsis; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; biosynthesis; gene expression regulation; Gene Knockdown Techniques; gene overexpression; genes; heat; heat shock response; heat stress; heat tolerance; hypersensitivity; inflorescence; inflorescences; mutants; plant thermotolerance; Proteins - genetics; Proteins - physiology; receptors; Reproduction; Seeds; sequence analysis; Signal Transduction; SPL; Thermotolerance; tobacco; transcription (genetics); transcription factor; transcription factors; Transcription Factors - genetics; Transcription Factors - physiology; Transcription, Genetic; transcription factor; abscisic acid; plant thermotolerance; SPL; inflorescence
• ISSN: 1674-2052; 1752-9867; 1752-9867
• DOI: 10.1016/j.molp.2017.03.010

Plant reproductive organs are vulnerable to heat, but regulation of heat-shock responses in inflorescence is largely uncharacterized. Here, we report that two of the SQUAMOSA PROMOTER BINDING PROTEIN- LIKE （SPL） transcriptional factors in Arabidopsis, SPL1 and SPL12, act redundantly in thermotolerance at the reproductive stage. The spll-1 sp112-1 inflorescences displayed hypersensitivity to heat stress, whereas overexpression of SPL 1 or SPL 12 enhanced the thermotolerance in both Arabidopsis and tobacco. RNA sequencing revealed 1939 upregulated and 1479 downregulated genes in wild-type inflorescence upon heat stress, among which one-quarter （1,040） was misregulated in spll-1 sp112-1, indicating that SPL1 and SPL12 contribute greatly to the heat-triggered transcriptional reprogramming in inflorescence. Notably, heat stress induced a large number of abscisic acid （ABA） responsive genes, of which -39% were disturbed in heat induction in spll-1 sp112-1 inflorescence. Preapplication of ABA and overex- pression of SPL1 restored the inflorescence thermotolerance in spll-1 sp112-1 and in the ABA biosynthesis mutant aba2-1, but not in the pyl sextuple mutant defective in ABA receptors PYR 1/PYL 1/PYL2/PYL4/PYL5/ PYL8. Thus, inflorescence thermotolerance conferred by SPL1 and SPL2 involves PYL-mediated ABA signaling. The molecular network consisting of SPL1 and SPL12 illustrated here shed new light on the mechanisms of plant thermotolerance at the reproductive stage.