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Background: Little leaf disease caused by phytoplasma infection is a significant threat to eggplant (also known as brinjal) cultivation in India. This study focused on the molecular characterisation of the phytoplasma strains and insect vectors responsible for its transmission and screening of brinjal germplasm for resistance to little leaf disease. Results: Surveys conducted across districts in the Tamil Nadu state of India during 2021–2022 showed a higher incidence of phytoplasma during the Zaid (March to June), followed by Kharif (June to November) and Rabi (November to March) seasons with mean incidence ranging from 22 to 27%. As the name indicates, phytoplasma infection results in little leaf (reduction in leaf size), excessive growth of axillary shoots, virescence, phyllody, stunted growth, leaf chlorosis and witches' broom symptoms. PCR amplification with phytoplasma-specific primers confirmed the presence of this pathogen in all symptomatic brinjal plants and in Hishimonus phycitis (leafhopper), providing valuable insights into the role of leafhoppers in disease transmission. BLAST search and phylogenetic analysis revealed the phytoplasma strain as "Candidatus Phytoplasma trifolii". Insect population and disease dynamics are highly influenced by environmental factors such as temperature, relative humidity and rainfall. Further, the evaluation of 22 eggplant accessions revealed immune to highly susceptible responses where over 50% of the entries were highly susceptible. Finally, additive main effect and multiplicative interaction (AMMI) and won-where biplot analyses identified G18 as a best-performing accession for little leaf resistance due to its consistent responses across multiple environments. Conclusions: This research contributes essential information on little leaf incidence, symptoms, transmission and resistance profiles of different brinjal genotypes, which together ensure effective and sustainable management of this important disease of eggplants. [ABSTRACT FROM AUTHOR]

Symptomatological and histopathological studies of phytoplsama on Ocimum gratissimum L. and Petunia species, growing in Patanjali campus, Haridwar, Uttarakhand were recorded. O. gratissimum L. showed symptoms as little leaf and witches' broom while Petunia sp. showed yellowing of leaves, witches' broom and stunting of stem. Phloem necrosis was also reported in infected plants of both genera. [ABSTRACT FROM AUTHOR]

In recent years, almond witches’-broom disease has been prevalent in almond growing areas in the centre and south of Iran. Furthermore, almond trees showing different symptoms of phytoplasma diseases such as little leaf, leaf rolling, dieback of branches, rosette and yellowing were observed in the central regions of Iran. DNA isolated from symptomatic almond trees was used to amplify 16S rDNA and 16S-23S rDNA intergenic spacer (IS) fragments by nested polymerase chain reaction (PCR) using phytoplasma universal primer pairs (P1/P7, R16F2/R2, PA2F/R and NPA2F/R). Phytoplasmas were detected in symptomatic almonds in two major almond-growing regions, Isfahan and ChaharMahal-O-Bakhtiari. Restriction fragment length polymorphism analyses of nested PCR products using endonuclease enzymes HpaII and TaqI revealed that phytoplasmas associated with infected almonds are genetically different. Sequence analyses of amplified fragments of 16S rDNA and IS region indicated that the almond phytoplasmas in Iran are closely related to ‘ Candidatus ( Ca.) Phytoplasma aurantifolia’, ‘ Ca. Phytoplasma phoenicium’, ‘ Ca. Phytoplasma solani’ and ‘ Ca. Phytoplasma trifolii’. The phytoplasmas related to ‘ Ca. Phytoplasma aurantifolia’ were more prevalent than other phytoplasmas in the central regions of Iran. [ABSTRACT FROM AUTHOR]