Molecular identification and characterization of “Candidatus Liberibacter spp.” from major citrus growing region of Malwa, Madhya Pradesh, India

Abstract

One of the most damaging diseases impacting yearly yield and productivity is huanglongbing, often known as greening of citrus fruits and plants. Huanglongbing is caused by the Candidatus Liberibacter species, of which three primary species are known worldwide: Candidatus Liberibacter africanus (CLaf), Candidatus Liberibacter americanus (CLam), and Candidatus Liberibacter asiaticus (CLas). In the current study, Candidatus Liberibacter infection and the occurrence of huanglongbing disease were examined in the Malwa region of Madhya Pradesh, which is home to the Nagpur Mandarin cultivar. A total of 100 samples were gathered for the current study from 14 villages in the chosen area, primarily Mandsaur, Neemuch, Ratlam, Ujjain, Dewas, Indore, Shajapur, Rajgarh, Dhar, and Jhabua. Here, out of 100 samples, 22 were determined to be positive, while the remaining 100 were negative despite having modest physiological and morphological characteristics that resembled symptoms of HLB. Sequencing results from 08 samples in the current investigation indicate that Candidatus Liberibacter asiaticus (05), Candidatus Liberibacter americanus (02), and Candidatus Liberibacter africanus (01) are all positive. In the study, eight 16S rRNA genes sequences targeting OI1/OI2c were submitted to GenBank with for Candidatus Liberibacter africanus (1) accession no: OQ725636.1 for Candidatus Liberibacter americanus (2) Accession: OQ725635.1 and OQ725634.1 and Candidatus Liberibacter asiaticus (5) for Accession: OQ725633.1, OQ725632.1, OQ725631.1, OQ725630.1 and OQ725629.1. Candidatus Liberibacter species isolated and sequenced in the current study had a greater degree of mutation (41 point mutations), according to single nucleotide polymorphism analysis. Present study provides occurrence and prevalence of Candidatus Liberibacter asiaticus as key causative agent for huanglongbing in the Nagpur Mandarin cultivar. Higher prevalence and occurrence of Candidatus Liberibacter species also affect other agriculture crops and hence a trend and pattern in genomic profile was investigated via SNP analysis that provides details of mutation. Genomic profile of Candidatus Liberibacter species is highly recommended for the development of antibacterial to tackle Candidatus Liberibacter species driven agriculture economical losses.