First report of rice bacterial leaf blight and grain discolouration caused by <i>Pantoea agglomerans</i> in India

A disease survey was carried out in Tamil Nadu, India during 2021 to assess the prevalence of diseases major rice-growing areas and characterise pathogens associated with infected plants. During survey, rice plants at seedling grain-filling stage showing water-soaked, elongated, light brown lesions leaf margins tips (Figure 1) were collected along grains a polythene bag, labelled sealed. Leaves yellowing drying from cut into small pieces, surface-sterilised 1% sodium hypochlorite for one minute, rinsed three times sterile distilled water then allowed air dry. After drying, tissues soaked 30 minutes room temperature 0.5 ml loop full suspension streaked onto nutrient agar (NA) medium. For isolation pathogen seed, discoloured grain samples surface sterilised 3% thrice Surface-sterilised placed Petri plate containing NA These plates incubated 28°C two days. Upon incubation, straw yellow-coloured colonies emerged. The further purified through single colony on NA. yellow colour, translucent undulate. 2.) exhibited umbonate surfaces slightly concave centres (Al-Kidsawey et al., 2020; Delétoile 2009). pathogenicity isolates demonstrated by inoculation seedlings (cv. Co 39). this, bacterial broth 48 hours 27°C. adjusted concentration 109 cfu/ml adding water. bacterium inoculated cutting tip (about 3 4 cm) fully expanded uppermost scissors dipping suspension. Controls used instead covered sheet overnight under laboratory conditions. leaves developed progressive necrosis colour shifts pale green within 14 days post inoculation, whereas control no symptoms. Koch's postulates fulfilled isolating which produced yellow, flat convex after incubation. subjected biochemical tests using KB002 HiAssorted Biochemical Test Kit (Himedia, Germany). showed positive reaction citrate utilisation, phenylalanine deamination, nitrate reduction, glucose arabinose utilization. It negative lysine ornithine utilization, urease, H2S production, adonitol, lactose sorbitol Based morphological characters tests, identified as Pantoea sp. To pathogen, DNA extraction done, PCR assay performed universal primers 27F 1492R targeting 16S rRNA gene. Sequencing amplicon revealed that had 93.7% identity agglomerans type strain SGAir0210 (GenBank Accession No. CP028033.1). partial gene sequences strains P. deposited GenBank (OP784578 OP784743). causing blight glume discolouration has been reported Brazil, South Korea, Turkey Venezuela (Aksoy & Boluk, 2019; Carrer Filho 2018; González 2015; Lee 2010). also causes infection humans 2009)). Bacterial caused stewartii subsp. indologenes (Vinodhini 2017). However, our knowledge, this is first report India. Further studies are needed ascertain commercial cultivars other parts We gratefully acknowledge facilities provided DST-FIST Lab, Department Plant Pathology, Nadu Agricultural University, Coimbatore,