Climate change, mainly in the form of global warming, has been reducing agricultural harvests, resulting in widespread risks of food insecurity and social problems. Maintaining the ability to feed the world’s population under conditions of global warming is a long-term challenge; understanding the molecular basis and genetic breeding of thermotolerant crops is a fundamental way to help meet this challenge.

Recently, a team led by Hong-Xuan Lin, at Shanghai Institute of Plant Physiology and Ecology (SIPPE), Shanghai Institutes for Biological Sciences reported the identi？cation of a major QTL from African rice (Oryza glaberrima), Thermo-Tolerance 1 (TT1), which is responsible for the strong ability of African rice to adapt to heat stress.

Using map-based cloning approach, after more than seven years’ efforts, Dr. Xin-Min Li in the lab of Hong-Xuan Lin and his colleagues successfully cloned TT1, which encodes an α2 subunit of the 26S proteasome involved in the degradation of ubiquitinated proteins that were denatured due to heat stress, thereby responding to high temperatures. Ubiquitome analysis demonstrated that TT1 enhances the degradation efficiency of proteasome, thereby facilitating the elimination and recycling of cytotoxic denatured proteins and the maintenance of heat response processes.

Interestingly, researchers elucidated that TT1 plays a key role in local adaptation during rice evolution, which may help explain how climate selection contributes to plant geographical distribution and evolution. More importantly, they demonstrated the potential of using TT1 to breed thermotolerant rice by marker-assisted selection (MAS) or transgenic techniques, as this gene increases rice grain yields up to 5~10-fold under heat stress without affecting any visible phenotype including agronomic traits. In addition, overexpression of TT1 in other plant species also greatly enhances their tolerance to heat stress, indicating that TT1 could be widely used to breed more thermotolerant cultivars of plants such as cruciferous vegetables and graminaceous crops including wheat.

“Our findings, including the novel insights about basic scientific issues and their substantial potential for practical applications, will be of importance to enhance crop productivity under global warming conditions”, said Prof. Hong-Xuan Lin. Meanwhile, it will also benefit the studies of rice evolution, plant local adaptation and so on.

This work entitled “Natural alleles of a proteasome α2 subunit gene contribute to thermotolerance and adaptation of African rice” was published in Nature Genetics on May 18^th, 2015.

This work was supported by grants from Ministry of Science and Technology of China, National Natural Science Foundation of China, CAS–Croucher Funding Scheme for Joint Laboratories, China Postdoctoral Science Foundation, and the Research Grants Council of Hong Kong.

CONTACT:
Hong-Xuan Lin
Shanghai Institute of Plant Physiology and Ecology
Shanghai Institutes for Biological Sciences
Chinese Academy of Sciences
300 Fenglin Road, Shanghai, 200032, China
Tel: +86-21-54924129, 54924132
Fax: +86-21-54924015
E-mail: hxlin@sibs.ac.cn