Journal
NEW PHYTOLOGIST
Volume 230, Issue 4, Pages 1476-1488Publisher
WILEY
DOI: 10.1111/nph.17255
Keywords
Cambium; cytokinin; Populus; secondary growth; secondary phloem
Categories
Funding
- National Key Research and Development Program [2016YFD0600105]
- National Science Foundation of China [32071791, 31870657, 31870175, 31800505, 31670669]
- Natural Science Foundation Project of CQ CSTC [cstc2018jcyjAX0477]
- Fundamental Research Funds for the Central Universities [XDJK2020B036]
- Chongqing Youth Top Talent Program [CQYC201905028]
Ask authors/readers for more resources
The study revealed that the local cytokinin signaling in the secondary phloem regulates cambial activity in a noncell-autonomous manner.
The regulation of cytokinin on secondary vascular development has been uncovered by modulating cytokinin content. However, it remains unclear how cytokinin enriched in developing secondary phloem regulates cambium activity in poplar. Here, we visualized the gradient distribution of cytokinin with a peak in the secondary phloem of poplar stem via immunohistochemical imaging, and determined the role of phloem-located cytokinin signaling during wood formation. We generated transgenic poplar harboring cytokinin oxidase/dehydrogenase (CKX)2, a gene encoding a cytokinin degrading enzyme, driven by the phloem-specific CLE41b promoter, indicating that the disruption of the cytokinin gradient pattern restricts the cambial activity. The RNA interference-based knockdown of the histidine kinase (HK) genes encoding cytokinin receptors specifically in secondary phloem significantly compromised the division activity of cambial cells, whereas the phloem-specific expression of a type-B response regulator (RR) transcription factor stimulated cambial proliferation, providing evidence for the noncell-autonomous regulation of local cytokinin signaling on the cambial activity. Moreover, the cambium-specific knockdown of HKs also led to restricted cambial activity, and the defects were aggravated by the reduced cytokinin accumulation. Our results showed that local cytokinin signaling in secondary phloem regulates cambial activity noncell-autonomously, and coordinately with its local signaling in cambium.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available