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 Researchers in our group answer basic scientific questions related to the constraints of cassava and sweetpotato production and develop biotechnology for bridging the gap of scientific discoveries and applications. We seek different transgenic approaches for increased starch production, enhanced resistance to diseases and abiotic stresses, and delayed post-harvest deterioration. Our goal is to make cassava and sweetpotato more productive a better source of food and biofuel production and profitable to grow.
Lab Homepage: http://www.cassavabiotech.org
Principal Investigator: Dr. Peng Zhang, Professor. Email: zhangpeng@sibs.ac.cn
Staff: Dr. Xiao-Guang Duan, Research Assistant; Dr. Qian Xu, Research Assistant; Hong-Xia Wang, Research Intern; Qiu-Xiang Ma, Research Intern; Min Zhang, Research Intern; Jia Liu, Research Intern; Chen Huang, Research Intern
Postdoctoral Fellow: Dr. Zhao-Rong Wei
Graduate Students: Jun Yang; Shan-Shan Zhao; Hui-Ping Bi; Dong An; Jia Xu; Wei-Juan Fan; Wen-Zhi Zhou; Jiao Liu
Visiting Scholars: Dr. Jorge Lopez Torres (National Centre of Tropical Crop Research [INIVIT], Villa Clara, Havana, CUBA); Cai-Xia Yin (College of Agriculture and Landscape, Zhongkai University of Agriculture and Engineering)
Senescence-Inducible Expression of Isopentenyl Transferase Extends Leaf Life, Increases Drought Stress Resistance and Alters Cytokinin Metabolism in Cassava
Cassava (Manihot esculenta Crantz) can withstand prolonged abiotic stress and survives by shedding its leaves. In its breeding programs, leaf retention has been considered an important agronomical trait for better leaf usage and biomass production. With the production of SAG12-IPT transgenic cassava we want to test the level of leaf retention and altered cytokinin metabolism of transgenic plants via the autoregulatory senescence inhibition system. After confirmation of transgene expression by molecular analysis and phenotype examination in greenhouse plants, two transgenic plant lines, 529-28 and 529-48, were chosen for further investigation. Detached mature leaves of 529-28 plants retained high levels of chlorophyll compared to wild-type leaves after dark-induced senescence treatment. The line 529-28 showed significant drought tolerance as indicated by stay-green capacity after drought stress treatment and its IPT expression was increased in the basal leaves of drought-stressed plants. Compared to wild-type, protein degradation was notably inhibited in the basal leaves of transgenic plants with or without drought treatment. Field experiment proved that leaf senescence syndrome was significantly delayed in 529-28 plants in comparison with wild-type and 529-48 plants. Physiological and agronomical characterizations of these plants also revealed that the induced expression of IPT had effects on photosynthesis, sugar allocation and nitrogen partitioning. Importantly, 9-28 plants accumulated high level of trans-zeatin-type cytokinins particularly of corresponding storage cosides to maintain cytokinin homeostasis. Our study proves the feasibility of prolonging the leaf life of a and also sheds a light on control of cytokinin homeostasis in cassava leaves.
Publications:
Liu GL, Zheng JL, Liu XM, Chen BF, Zhang P. (2008) Grey relational analysis of storage root yield and above-ground traits in different sweetpotato genotypes. In: Sustainable sweetpotato production technology for food, energy, health and environment- the proceedings of 3rd China-Japan-Korea workshop on sweetpotato (Q.C. Liu, Ed). China Agricultural University Press, Beijing, 221-228. Vanderschuren H, Akbergenov R, Pooggin M, Hohn T, Gruissem W, Zhang P. (2007) Transgenic cassava resistance to African cassava mosaic virus is enhanced by viral DNA-A bidirectional promoter-derived siRNAs. Plant Molecular Biology 64: 549-555. Vanderschuren H, Stupak M, Fütterer J, Gruissem W, Zhang P. (2007) Engineering resistance to geminiviruses - Review and perspectives. Plant Biotechnology Journal 5: 207-220. Zhang P, Vanderschuren H, Fütterer J, Gruissem W. (2005) Resistance to cassava mosaic disease in transgenic cassava expressing antisense RNAs targeting virus replication genes. Plant Biotechnology Journal 3: 385-397.
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