Reference "Cloning and analysis of a new NBS-LRR resistance gene family in rice"

Reference ID

32586

Title

Cloning and analysis of a new NBS-LRR resistance gene family in rice

Source

Acta genetica Sinica, 2005, vol. 32, pp. 704-711

Authors (7)

Wang-S-Q	Zhang-D-C
Li-P	Wang-X-D
Li-S-G	Zhu-L-H
Zhai-W-X

Abstract

Sequence-based gene isolation has been a practical approach for plant resistance
gene cloning. In this study, RS13, a cloned rice sequence with the NBS (nucleotide-
binding site) domain of resistance genes, was used as a probe to screen a
bacterial artificial chromosome (BAC) library of rice variety IR64,and four
positive clones were obtained. Of them the clone 14E19 covered the other three
clones and was sequenced through a shotgun approach. The whole sequence of the
insert fragment of 14E19 was assembled into approximately 73 kb in length. Genes
on the whole assembled sequence were predicted,and four genes encoding NBS and
LRR (leucine-rich repeat) domains were found, named as NL-A, B, C and D
respectively. For further analysis, another longer BAC clone,106P13, covering
14E19 on the same chromosome position was identified from a BAC library of
IRBB56 which had the same genome background with IR64. Ten NL-homologous copies
were discovered on the sequence of the BAC clone 106P13, and four copies were
identical with those on 14E19. The similar homologous sequences were also found
in the genomic sequences of Nipponbare,93-11 and Guangluai4. However, NL
sequences were less homologous with the known NBS-LRR resistance genes. This
result indicated that NL was a new NBS-LRR gene family and was composed of ten
members at least. RT-PCR and cDNA screening displayed that NL-B expressed in a
bacterial blight-resistant rice variety IRBB4, indicating the gene was possibly
involved in resistance reactions.