Overexpression of a Poplar RING-H2 Zinc Finger, Ptxerico, Confers Enhanced Drought Tolerance via Reduced Water Loss and Ion Leakage in Populus.

Min-Ha Kim,Hyoshin Lee,Jae-Heung Ko,Eun-Kyung Bae,Young-Im Choi,Jin-Seong Cho,Kyung-Hwan Han,Eung-Jun Park

doi:10.3390/ijms21249454

Abstract

Drought stress is one of the major environmental problems in the growth of crops and woody perennials, but it is getting worse due to the global climate crisis. XERICO, a RING (Really Interesting New Gene) zinc-finger E3 ubiquitin ligase, has been shown to be a positive regulator of drought tolerance in plants through the control of abscisic acid (ABA) homeostasis. We characterized a poplar (Populus trichocarpa) RING protein family and identified the closest homolog of XERICO called PtXERICO. Expression of PtXERICO is induced by both salt and drought stress, and by ABA treatment in poplars. Overexpression of PtXERICO in Arabidopsis confers salt and ABA hypersensitivity in young seedlings, and enhances drought tolerance by decreasing transpirational water loss. Consistently, transgenic hybrid poplars overexpressing PtXERICO demonstrate enhanced drought tolerance with reduced transpirational water loss and ion leakage. Subsequent upregulation of genes involved in the ABA homeostasis and drought response was confirmed in both transgenic Arabidopsis and poplars. Taken together, our results suggest that PtXERICO will serve as a focal point to improve drought tolerance of woody perennials.

Highlights

Drought stress is one of the major environmental problems in the growth of plants, including both crops and woody perennials
Our results suggest that PtXERICO is most likely orthologous to AtXERICO
We found that PtXERICO, the closest homolog of XERICO from poplar (P. trichocarpa), shared a high sequence similarity with the conserved TM and RING-H2 zinc finger motif (Figure 1a)

Summary

Introduction

Drought stress is one of the major environmental problems in the growth of plants, including both crops and woody perennials. The RING (Really Interesting New Gene) domain-containing proteins are known to have E3 ubiquitin ligase activity, which controls protein degradation through the ubiquitin-proteasome system in various species [7,8]. The most abundant E3 enzymes were RING-type E3 ubiquitin ligases [9] and a total of 469 predicted RING proteins have been reported in Arabidopsis [10,11]. Many E3 ubiquitin ligases regulate plant growth and development. COP1, the first RING finger gene from Arabidopsis, has been identified to negatively regulate photomorphogenesis [12], and BIG BROTHER controls organ size by reducing cell proliferation [13]

Methods

Results

Conclusion