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ZEITLUPE is required for shade avoidance in the wild tobacco Nicotiana attenuata
Author(s) -
Zou Yong,
Li Ran,
Baldwin Ian T.
Publication year - 2020
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.12880
Subject(s) - phytochrome , biology , shade avoidance , circadian clock , botany , photoperiodism , hypocotyl , arabidopsis , microbiology and biotechnology , mutant , red light , gene , genetics
Being shaded is a common environmental stress for plants, especially for densely planted crops. Shade decreases red: far‐red (R:FR) ratios that inactivate phytochrome B (PHYB) and subsequently release p̱hytochrome i̱nteraction f̱actors (PIFs). Shaded plants display elongated hypocotyls, internodes, and petioles, hyponastic leaves, early flowering and are inhibited in branching: traits collectively called the shade avoidance syndrome (SAS). ZEITLUPE (ZTL) is a circadian clock component and blue light photoreceptor, which is also involved in floral rhythms and plant defense in Nicotiana attenuata . ztl mutants are hypersensitive to red light and ZTL physically interacts with PHYB, suggesting the involvement of ZTL in R:FR light signaling. Here, we show that N. attenuata ZTL‐silenced plants display a phenotype opposite to that of the SAS under normal light. After simulated shade, the normally induced transcript levels of the SAS marker gene, ATHB2 are attenuated in ZTL‐silenced plants. The auxin signaling pathway, known to be involved in SAS, was also significantly attenuated. Furthermore, NaZTL directly interacts with NaPHYBs, and regulates the transcript levels of PHYBs, PIF3a, PIF7 and PIF8 under shade. Our results suggest that ZTL may regulate PHYB‐ and the auxin‐mediated signaling pathway, which functions in the SAS of N. attenuata .