The Chinese Academy of Thermal Sciences revealed the molecular mechanism of CC glutamine oxygen-mediated reactive oxygen species balance regulating cassava drought resistance

Manihot esculenta Crantz is an important tropical crop and is one of
the main food crops in tropical regions such as Africa.
With a carbohydrate content of 38% and a multivitamin content, it is the main food source
for more than 1 billion people worldwide.
During the planting process, the seedling stage and root formation period of cassava overlap with the dry season in tropical areas, and drought has a very large impact on
the yield and quality of cassava.
Therefore, identifying important drought-resistant genes of cassava and improving the adaptability of cultivated cassava to drought are of great significance
for China's "tropical agriculture going out" to support the national "Belt and Road" strategy and maintain world food security.

 

Reactive oxygen species balance plays a key role
in plants' response to drought stress.
Glutamine is an important component in maintaining reactive oxygen species balance in plants, but its molecular mechanism for regulating plant drought stress response through reactive oxygen species balance remains to be explored
。 Recently, the Plant Biotechnology Journal published a report online in the authoritative journal "CC-type glutaredoxin, MeGRXC3, associates with catalases and negatively regulates drought tolerance in cassava.
" The research paper (Manihot esculenta Crantz)" confirmed that CC glutadoxin MeGRXC3 can regulate catalase activity at the transcriptional and post-transcriptional levels, affect the distribution of hydrogen peroxide in different types of cells in the leaf epidermis, and thus regulate the response
of cassava to drought stress.
The results of the study are helpful to understand the complex mechanism of glutamine to regulate the drought stress response of cassava through reactive oxygen species balance, and at the same time provide genetic resources and scientific basis
for the use of key genes to cultivate drought-resistant and high-yield cassava varieties.

 

In 100 cultivated cassava germplasms, the team determined that MeGRXC3 was significantly correlated with catalase activity in cassava leaves under drought stress through resequencing of target intervals and the correlation
analysis of drought resistance indicators.
Through the phenotypic analysis of drought resistance of transgenic cassava, it was found that MeGRXC3 negatively regulates drought and abscisic acid-induced stomatal closure, thereby affecting the drought tolerance
of transgenic cassava.
Further analysis found that MeGRXC3 can antagonistically regulate the distribution
of hydrogen peroxide in epithelial septal cells and guard cells in cassava leaves.

 

Using protein co-precipitation technology, the research team screened three catalase proteins that may interact with MeGRXC3 from tapioca leaves, and then confirmed that MeGRXC3 can bind to catalase MeCAT1 and MeCAT2, respectively, and regulate its catalase activity
。 Not only that, the research team found that MeGRXC3 can regulate the expression of multiple stress-related transcription factor genes by interacting with the transcription factor MeTGA2 in the nucleus, and regulate the expression of catalase MeCAT7 gene through the transcription factor MeMYB63, thereby regulating catalase activity
at the transcriptional level.
The above studies have opened up a new perspective on the molecular mechanism of reactive oxygen species balance regulating plant drought stress response, and at the same time demonstrated the potential application value
of MeGRXC3 gene in improving the yield of cassava root in arid environment.

 

This study was completed under the guidance of researcher Peng Ming of the Sanya Research Institute of the Chinese Academy of Tropical
Agricultural Sciences.
Dr.
Guo Xin and Associate Researcher Yu Xiaoling of the Institute of Biology are the co-first authors of the paper, and Associate Professor Ruan Mengbin is the corresponding author
of this paper.
Xu Ziyin, a 2020 master's student in the School of Tropical Crops of Hainan University, Zhao Pingjuan, an associate researcher of the Institute of Biology, Zou Liangping and Li Wenbin, an assistant researcher, Zhang Peng, a researcher at the Center for Excellence in Molecular Plant Science Innovation of the Chinese Academy of Sciences, and Dr.
Geng Mengting of Hainan University, also participated in the research
.
This research has been funded
by the National Key R&D Program, the Major Science and Technology Program of Hainan Province, the Basic Scientific Research Business Expenses of Central-level Public Welfare Research Institutes, and the Yazhou Bay Seed Laboratory.

 

The functional gene research team of the Institute of Biology mainly focuses on the important tropical crops casssava and banana as the research object, conducts research on the molecular mechanism of tropical crops in response to environmental stress, and excavates important functional genes and non-coding RNAs to promote the development of biological breeding technology of
tropical crops.
The team members are all "high-level talents of Hainan Free Trade Port", including 1 "top-notch talent" of tropical agricultural young talents
.
Since its establishment, the team has presided over 1 national "973" program project, 1 national natural science foundation international (regional) cooperation project, 1 national natural science foundation project, 3 national natural science foundation youth fund projects, and participated in the national key research and development program, the national 863 plan, the science and technology support plan, the
major research and development plan of Hainan Province and many other projects 。 In the past five years, the team has made important progress in the mining of cassava stress resistance mechanism and important functional genes, and has published in the internationally renowned professional journal Plant Biotechnology Journal, Plant, Cell & Environment, Theoretical and Applied Genetics, Journal of Experimental Botany, BMC Plant Biology, Frontiers in Plant Science and other related papers have published more than 10 related papers, committed to contributing to the development of basic research on tropical crops
.

 

Related papers full text link: https://doi.
org/10.
1111/pbi.
13920