IDENTIFICATION AND MOLECULAR CHARACTERIZATION OF WILD SPECIES OF RICE FOR RESISTANCE TO BACTERIAL BLIGHT
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Date
2024-04-30
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Acharya N G Ranga Agricultural University
Abstract
WILD RICE are known to be a resources for many useful biotic and abiotic
resistant genes which can be used in improvement of rice. They are reported to be
resistant to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo)
which causes severe infection in rainfed and irrigated conditions especially yield
loss. Till now 46 different bacterial blight resistant genes are identified from
diverse genotypes out of that 12 genes were identified from wild species
The current study was aimed to identify and characterize wild rice accessions for
resistance to bacterial blight. One hundred and sixteen wild rice accessions
comprising of 63 accessions of Oryza rufipogon, nine of Oryza nivara, four of
Oryza officinalis, four of Oryza latifolia, five of Oryza australiensis, two of Oryza
minuta, five of Oryza punctata, three of Oryza eichingeri, five of Oryza
rhizomatis, two of Oryza longistaminata, two of Oryza barthii, one of Oryza
glumipatula, one of Oryza ridleyi, four of Oryza alta, one of Oryza longiglumis,
four of Oryza grandiglumis and one of Oryza meridionalis along with susceptible
check Samba Mahsuri are screened for Bacterial Blight resistance for three seasons
Kharif 2020, Rabi 2020-21, Kharif 2021. Artificial inoculation of bacterial strain
IXO-20 was done at maximum tillering stage by leaf clip inoculation method and
disease score was taken after 14 days and 21 days of inoculation. Considering the
performance of accessions of different wild species across three seasons 40
xiii
promising accessions showing consistence and high level of resistance e mean
lesion length data, 40 resistant accessions which had shown consistent resistance
both on 14 and 21 days after inoculation over the three seasons were used for
characterization of BB resistant genes.
40 promising accessions comprising of 22 of Oryza rufipogon, two of Oryza
nivara, three of Oryza officinalis, two of Oryza latifolia, two of Oryza
australiensis, one of Oryza minuta, two of Oryza punctata, three of Oryza
eichingeri, one of Oryza rhizomatis, two of Oryza alta identified for bacterial leaf
blight resistance were characterised for 11 Xa genes viz., Xa4, xa5, xa13, Xa21,
Xa23, Xa27, Xa32, Xa33, Xa35, Xa38 and Xa41(t) using gene specific markers
RM224, xa5FM, xa13 PROMOTER, pTA248, RM254, BDTG19, RM5926,
RMWR7.1-7.6,RM144, Oso4g53050-1, Osweet-14 respectively. Out of the 40 BB
resistant accessions, seven accessions shown the presence of single gene 10
accessions had shown the presence of two genes, 12 accessions were with three
genes, whereas two accessions with combination of four genes and one accessions
with five genes.
Molecular characterisation of BB resistance genes showed that 4 accessions
(IC521672, EC861677, EC861700, EC861711) did not show the presence of any
gene studied indicating the possibility of novel gene conferring BB resistance in
these accessions. It is further inferred that they are no reported BB resistant genes
in Oryza latifolia and Oryza punctata which showed high level of resistance in
present study indicating that novel gene conferring BB resistance, However,
further inheritance and mapping studies are required to be carried out to ascertain
the novelty of the sources.