J Integr Plant Biol. ›› 2015, Vol. 57 ›› Issue (9): 757-769.DOI: 10.1111/jipb.12363

• Cell and Developmental Biology • Previous Articles     Next Articles

Characterization of tub4P287L, a β-tubulin mutant, revealed new aspects of microtubule regulation in shade

Jie Yu1,2†, Hong Qiu1,2†, Xin Liu1, Meiling Wang1, Yongli Gao1, Joanne Chory3,4 and Yi Tao1,2*   

  1. 1School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, China
    2State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
    3Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California, USA
    4Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA
  • Received:2015-01-27 Accepted:2015-04-14 Published:2015-04-21
  • About author:These authors contributed equally to the paper.
    *Correspondence: E-mail: yitao@xmu.edu.cn

Abstract:

When sun plants, such as Arabidopsis thaliana, are under canopy shade, elongation of stems/petioles will be induced as one of the most prominent responses. Plant hormones mediate the elongation growth. However, how environmental and hormonal signals are translated into cell expansion activity that leads to the elongation growth remains elusive. Through forward genetic study, we identified shade avoidance2 (sav2) mutant, which contains a P287L mutation in β-TUBULIN 4. Cortical microtubules (cMTs) play a key role in anisotropic cell growth. Hypocotyls of sav2 are wild type-like in white light, but are short and highly swollen in shade and dark. We showed that shade not only induces cMT rearrangement, but also affects cMT stability and dynamics of plus ends. Even though auxin and brassinosteroids are required for shade-induced hypocotyl elongation, they had little effect on shade-induced rearrangement of cMTs. Blocking auxin transport suppressed dark phenotypes of sav2, while overexpressing EB1b-GFP, a microtubule plus-end binding protein, rescued sav2 in both shade and dark, suggesting that tub4P287L represents a unique type of tubulin mutation that does not affect cMT function in supporting cell elongation, but may affect the ability of cMTs to respond properly to growth promoting stimuli.
 

Yu J, Qiu H, Liu X, Wang M, Gao Y, Chory J, Tao Y (2015) Characterization of tub4P287L, a b-tubulin mutant, revealed new aspects of microtubule regulation in shade. J Integr Plant Biol 57: 757–769 doi: 10.1111/jipb.12363

Key words: Arabidopsis, microtubules, plant hormones, shade

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