TITLE:
Molecular Screening of Rice Cultivated in Benin for the Identification of Xanthomonas oryzae Pv. oryzae and Bacterial Leaf Blight Resistance Genes
AUTHORS:
Chimène Nadège Mahoussi Nanoukon, Koffi David Montcho Hambada, Antoine Abel Missihoun, Kéllya Laurinzo Déguénon, Bignon Meyrix Pamela Franzel Loumédjinon, Bana Wêtè Déré Félicité Bio, Emilienne Zinsou, Réel Gael Fael Houngbélagnon, Amed Sèmèvo Havivi, Lamine Baba-Moussa, Lambert Gustave Djédatin
KEYWORDS:
Bacterial Blight, Xanthomonas oryzae Pv. oryzae, Molecular Characterization, Resistance Genes
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.14 No.12,
December
21,
2023
ABSTRACT: One of the most devastating diseases of rice worldwide is bacterial
blight (BLB) caused by Xanthomonas oryzae pv. Oryzae (Xoo). In Benin, Xoo was first described in 2013 on wild
rice Oryzae longistaminata. So far, no study has been done on Beninese Xoo
strains. We do not know whether the pathogen has already passed into the rice
varieties grown, or if they are exposed to other bacteria. Whereas the use of
resistant varieties, carrying resistance genes, is the only highly effective
and environmentally friendly way to control this disease, no information is
available on these Xoo resistance genes in rice varieties grown in Benin apart
from the one we recently. This study aims to identify Beninese Xoo strains, causing
BLB and screen rice varieties grown in Benin for the main resistance genes.
Diseased rice leaves showing typical symptoms of fire blight collected from
different rice fields in the three phytogeographic areas of Benin were analyzed
by PCR for Xoo-specific sequence identification.
Furthermore, seventy-five collected rice accessions were screened to identify
xa5, Xa7, xa13, and Xa21 resistance genes to Xoo. The results reveal that Xanthomonas oryzae was
identified in two fields in Banikouara and one in Malanville. On the other
hand, Sphingomonas sp. has been
identified in several other rice fields in Benin. Forty-seven of seventy-five
rice accessions examined (62.66%) carried Xoo resistance genes with 3 (4%) and
40 (53.33%) of xa5 and Xa21 respectively. None of the accessions had either Xa7
or xa13 resistance genes. Three accessions possess both xa5 and Xa21 genes.
Isogenic lines IRBB60 and IRBB21, supposed to
be a positive control, presented a Xoo sensitivity allele. These results
indicate that Xoo has moved from the wild rice variety to the cultivated variety
in northern Benin and varietal improvement programs must be implemented with
varieties having several resistance genes for the efficient response against a
possible BLB pandemic in Benin.