Mango burl is an important disease affecting many mango plantations in India and causes great loss in yield and decrease of vigour. We carried out a diagnostic survey for burl disease (sometimes also referred to as crown gall) in different varieties of mango (Mangifera indica L., Anacardiaceae) throughout India during 2015 and 2016. More than 500 mango genotypes were screened for disease susceptibility and more than twenty-three mango genotypes in different parts of India were found susceptible to this disease. Burls initiate as small tumorous growths and become more pronounced as warty outgrowths with the increasing age of the individual tree. Samples of burl were collected from all popular varieties from different parts of the country and subjected to histological investigations.The present study confirms that mango burl disease is caused by Agrobacterium tumefaciens using evidence from the “carrot assay” and molecular identification of the presumed causal organism. The latter was isolated and inoculated on carrot disks to induce typical symptoms.The xylem of the burl tissue was deformed and showed no specific orientation of the wood cells. Dimensional details and morphology of xylem cells vary at different positions within the burl. In a 10 cm diameter burl, the marginal portion showed xylem cells in circular arrangement. Vessel elements and fibres were very short while rays were relatively low and biseriate rays were observed rarely. Orientation of the xylem tissue was lost and all three plains (i.e. transverse, tangential and radial view) were observed in the same section. Cells from the middle portion of the burl were isodiametric, oval to circular, thick-walled and lignified, in morphology not dissimilar from callus tissue. Tyloses were common in all the cell types viz. fibres, ray cells, tracheids, axial parenchyma cells, and vessel elements.
Itajahya galericulata (Phallales, Phallaceae) was previously reported from several countries in South America and Africa. Recently we found I. galericulata in the city of Vadodara, Gujarat State, India. To verify its identity we studied its morphology and performed molecular phylogenetic analyses using nuclear rDNA LSU and mitochondrial ATP6 loci. Here we also provide nuclear rDNA ITS sequences for the Indian collection, since up to now no sequences of this region have been available for I. galericulata in GenBank. This study furnishes the first evidence for the occurrence of I. galericulata in India and in Asia as a whole.
A new species, Ophioglossum gujaratense, is described from Gujarat state (India). It resembles O. polyphyllum in the presence of sheathing rhizomorph and 1–4 (rarely 5) trophophylls. On the other hand, rhizomorph morphology, common stalk, trophophyll arrangement, leaf lamina and leaf base make it distinct from O. polyphyllum. Stoloniferous roots, trophophyll number and their arrangement of the new species also resemble O. parvifolium and O. nudicaule. However, both these species lack a sheath around the leaf-stem base. A comparative account of morphologically similar species, viz. O. gujaratense, O. polyphyllum, O. parvifolium and O. nudicaule is provided. The distinctness of the new taxon has been confirmed using molecular data from chloroplast genome markers viz rbcL, trnH-psbA, trnF-trnE and trnL-trnF.
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