Cytokinin and auxin regulates WUS induction and inflorescence regeneration in vitro in Arabidopsis.
Inflorescence regeneration in vitro provides a simplified approach for the study of inflorescence development. In this study, high frequency of regenerated inflorescences was established using Arabidopsis stage-10 pistil as the explants on the inducing medium containing the 2 mg/L zeatin and 0.01 mg/L indole-3-acetic acid. TERMINAL FLOWER 1 (TFL1) expression was detected in callus at 6 days after transferred to inducing medium, and LEAFY (LFY) expression was detectable subsequently, suggesting that both genes play important roles as they function on inflorescence development in the plant. To investigate the formation of the stem cell organizing center, we examined the WUSCHEL (WUS) and CLAVATA3 (CLV3) expression within callus during inflorescence regeneration. WUS signals start to accumulate on callus at 4 days after induction, and then, the CLV3 signals are induced on callus at 5 days on the inflorescence-inducing medium. The expression domain of WUS is below that of CLV3, indicating that the patterns of the organizing center and stem cell formation are similar to that in zygotic and somatic embryogenesis. However, more cells of the organizing center were observed within callus than pro-embryo, suggesting that inflorescence differentiation requires more cells of the organizing center. Furthermore, it was found that the WUS expression is controlled by the ratio of cytokinin with auxin. The results suggest that other factors besides WUS and CLV3 are required for inflorescence regeneration.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018, Shandong, China.
Zhi Juan
ZJ
Cheng
Shan Shan
SS
Zhu
Xin Qi
XQ
Gao
Xian Sheng
XS
Zhang
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003583:Cytokinins / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000494:pharmacology*; D056626:Inflorescence / Q000254:growth & development*; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism
C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; D003583:Cytokinins; D018398:Homeodomain Proteins; D007210:Indoleacetic Acids; C074747:LFY protein, Arabidopsis; D018749:RNA, Plant; C102864:TFL1 protein, Arabidopsis; D014157:Transcription Factors; C116421:WUSCHEL protein, Arabidopsis