Wednesday, November 15, 2006
270-3

Molecular Characterization of Myb Transcription Factor (TaMyb) Gene that is Expressed in Response to Hypoxic Condition in Wheat (Triticum aestivum L.) Roots.

Tong Geon Lee1, Cheol Seong Jang1, Jae Yoon Kim1, Jae Han Park1, Dae Yeon Kim1, Dong Sub Kim2, and Yong Weon Seo1. (1) Korea University, Div. of Biotechnology, College of Life Sciences & Biotechnology, Anam-Dong, Seogbuk-Gu, Seoul, 136-713, South Korea, (2) Korea Atomic Energy Research Institute, Department of Radiation Plant Breeding and Genetics, Advanced Radiation Research Institute, Sinjeong 1266, Jeongeup, Jeonbuk, 580-185, South Korea

Plant roots encounter environmental stresses such as water deficit, nutritional changes directly. These stresses limit growth and productivity of crops. Molecular characterization of Myb transcription factor (TaMyb) from wheat roots shows numerous possibilities of a function of Myb transcription factor under abiotic stresses. TaMyb transcription levels gradually increased as the result of treatment with NaCl. Slight increases in expression were noted during the early stages of exogenous treatment of with both PEG and ABA. In a condition of gradual oxygen decline one, dramatic increases in the transcripts of a TaMyb gene in roots occurred under hypoxia. The transcriptional expression of TaMyb was continued until approximate anoxia, but little expression during anoxia. In the leaves, however, TaMyb expression increased under anoxia, not hypoxia. Differential TaMyb expression between leaves and roots indicates that TaMyb might have tissue specific functions with regard to its responses to anaerobic stress. TaMyb under hypoxia showed tissue specific distributions in roots. The expression was high in the epidermis, endodermis and the cortex adjacent to the endodermis but was not detected at all in the vascular tissues or cortex which contained aerenchyma under hypoxic conditions. It is possible that the decreasing oxygen concentrations in the root environment are initially detected by the root epidermis followed by endodermis adjacent to the cortex and vascular systems. The expression was also high in the cortex proximal to the developing lateral roots as well as the meristematic zone of the developing lateral roots. Our data suggest that the expression of TaMyb could be directly related to the wheat responses to abiotic stresses and organ development.

This work was supported by a grant (20050301-034-432-006-01-00) from BioGreen 21 Program, Rural Development Administration, Republic of Korea.


Handout (.ppt format, 10734.0 kb)

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