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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]

Cathranthus roseus also known as periwinkle, an ornamental plant contains several medicinal values, was found with the symptoms of little leaf and witches' broom at Shahjahanpur location with the incidence of up to 8%. The phytoplasma etiology was confirmed through scanning electron microscopy examination in all the four-leaf samples. Molecular analysis through PCR with universal primer pairs P1/P6 followed by nested PCR with R16F2n/R16r2 primers yielded ~1.2kbp amplicons in all the four symptomatic leaf samples. One amplicon was eluted, purified, sequenced, and used in BLASTn searches, which showed maximum identity of periwinkle isolate with several isolates of 16SrIX group of phytoplasma. Further, phylogenic analysis and in silico RFLP confirmed the association of 16SrIX-C subgroup phytoplasma in little leaf and witches broom plants which is the first report from India. [ABSTRACT FROM AUTHOR]

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Abstract: A large‐scale survey was conducted on pistachio plants exhibiting foliar symptoms including scorch, little leaf, yellows and reddish in pistachio growing areas in the Qom, Yazd and Qazvin provinces of Iran. Total DNA was extracted from symptomatic and symptomless pistachio and used in nested PCR assays with phytoplasma universal primers. Nested PCR products were obtained for symptomatic plant samples while the symptomless plants yielded no PCR products. Virtual restriction fragment length polymorphism, phylogenetic and DNA homology analyses of partial 16S ribosomal sequences of phytoplasma strains associated with symptomatic plants revealed the presence of phytoplasmas referable to two ribosomal groups; in particular, “Candidatus Phytoplasma solani” and “Ca. P. phoenicium” were identified. The presence of these phytoplasmas in pistachio is of great phytosanitary significance due to its commercial interest. [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]

The article presents a study conducted to gain information regarding the diseases affecting bamboos planted in nurseries and plantations in Wayanad, India. During the study, causal agents of disease underwent isolation and there pathogens tested. The study found out that causal agents including Fusarium moniliforme and Botryobasidium salmonicolor caused culm rot and thread blight respectively. The diseases found in bamboos can be eliminated through fungicides and surface burning.

White clover plants showing little leaf and leaf reddening symptoms were observed in Isfahan Province in central Iran. Restriction fragment length polymorphism analyses of nested PCR-amplified fragments from Iranian clover little leaf phytoplasma isolates and representative phytoplasmas from other phytoplasma groups using Alu I, Cfo I, Kpn I and Rsa I restriction enzymes indicated that the clover phytoplasma isolates are related to the peanut WB group. Sequence analyses of partial 16 S r RNA fragments showed that Iranian clover little leaf phytoplasma has 99% similarity with soybean witches'-broom phytoplasma, a member of the peanut WB (16 Sr II) phytoplasma group. This is the first report of clover infection with a phytoplasma related to the 16 Sr II group. [ABSTRACT FROM AUTHOR]

Sugar beet ( Beta vulgaris L. subsp. vulgaris var. altissima) is a biennial, sugar-producing tuber crop grown in different parts of the world. Diseased sugar beets with symptoms of little leaf were observed during 2008 in Tamil Nadu, India. Phytoplasmas were detected in symptomatic leaves of three separate plants using PCR with primer pair fU5/rU3, which amplify an 880-bp fragment of the 16S rRNA region of phytoplasmas. The nucleotide sequence analysis of a 766-bp fragment had 100% identity among the sequence from the three plants (GQ184437) and 96% nucleotide sequence identity with 16S ribosomal RNA gene sequences of eggplant phyllody phytoplasma. [ABSTRACT FROM AUTHOR]