Submitted to: Genome
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/26/2004
Publication Date: 12/3/2004
Citation: Jiang, S.M., Zhang, L., Hu, J., Shi, R., Zhou, G.H., Chen, Y.H., Yin, W.B., Wang, R., Hu, Z.M. 2004. Screening and analysis of differentially expressed genes from an alien addition line of wheat-thinopyrum intermedium induced by barley yellow dwarf virus infection. Genome 47:1114-1121 Interpretive Summary: Intermediate wheatgrass has been a valuable genetic resource of resistance to pests or tolerance to abiotic stresses for wheat improvement. Many useful genes have been transferred and deployed in wheat cultivars. Molecular tags for these transferred genes will be highly desired in marker-assisted-selection that circumvents the need to carry out actual pest or stress screening. Screening for resistance to barley yellow dwarf virus (BYDV) is laborious, costly and time-consuming. Using molecular techniques, we identified candidate genes that were involved in wheat plant's response to BYDV infection. Seven of nine candidate genes were present in the wheatgrass chromosome that confers the resistance to BYDV. These expressed genes can be used either as molecular markers for isolating the gene(s) conferring BYD resistance or as selection tools for identifying transferred alien chromosome segments in wheat germplasm lines.
Technical Abstract: The alien addition line TAI-27 contains a pair of chromosomes of Thinopyrum intermedium that carries the resistance gene against Barley Yellow Dwarf Virus (BYDV). A subtractive library was constructed using the leaves of TAI-27, which were infected by aphid carried GAV strain of BYDV, and the control at the three-leave developmental stage. Nine differentially expressed genes were identified from one hundred clones picked randomly and sequenced. Two of the nine clones are highly homologous with known genes. Of the remaining seven cDNA clones, five clones matched known expressed sequence tags (ESTs) sequences from wheat and/or barley whereas the other two clones are unknown. Five of the nine differentially expressed sequences (WTJ9, WTJ11, WTJ15, WTJ19, WTJ32) are highly homologous with ESTs from wheat or barley challenged with pathogens. The five sequences and another one (WTJ18) are also highly homologous with ESTs of abiotic stresses in wheat or barley. Reverse Northern hybridization results showed that seven of the nine differentially expressed cDNA sequences could be hybridized with cDNA of Th. intermedium infected by BYDV. Three of these can also be hybridized with cDNA of line 3B-2 (a parent of TAI-27) infected by BYDV. The alien chromosome in TAI-27 was microdissected. The second round LA-PCR products of the alien chromosomal DNA were labeled with digoxygenin (DIG) and used as the probe to hybridize with the nine differentially expressed genes. The analysis showed that seven differentially expressed genes are homologous with the alien chromosome of TAI-27. These seven differentially expressed sequences could be used as ESTs of the alien chromosome of TAI-27. This research laid the foundation for screening and cloning of new specific functional genes conferring resistance to BYDV, and probably other pathogens.