Origin of Alternaria kashmeriana Causing Canker Stains on Native Platanus orientalis kashmeriana - A First Report from the Asia

Platanus orientalis L., the oriental plane perennial woody tree [1] with important riparian species [2] is widely spread in Crete and other southern islands. Its natural spread ranges from the southern Balkans, Crete, mountains of Turkey, Syria, Iran and Iraq, eastwardly to Kashmir valley, where it is familiarly known as the ‘chinar’. Chinar, Platanus orientalis kashmeriana, is the lone species of family Platanaceae found in India and growing throughout the valley of Kashmir. The family, Platanaceae consists of only a single living genus Platanus and is a native of the eastern Mediterranean portion from where it spread eastwards. It is a large deciduous tree, native to temperate regions (Huxley, 1992). Pharmacologically, the buds are used in folk medicine as antiseptic and antimicrobial medication of the urinary system [1]. Plane has distinct advantages such as rapid growth rate, easy propagation, lush foliage and also strong air purification ability. Canker stain of plane tree, caused by the fungus Ceratocystis platani is a lethal disease that attacks Platanus sp [3] was earlier reported from the United States and Europe [4-6]. The disease results in staining of the xylem, distraction of osmotic movement, cankers, and finally death of the tree [4]. The first report of the disease was observed in Greece in the 2003 on oriental plane in the southwestern Peloponnese [7], where C. platani has caused considerable mortality of the oriental plane in natural stands such as streams, rivers as well as in ornamental plantings in London plane [7]. During the mycological explorations to the northern India (Kashmir), similar canker stain type symptoms were observed on beneath of the leaf surfaces of Platanus orientalis kashmeriana to what has been reported earlier in United States and Europe. In this study, the genetic variation was assessed in nuclear rDNA in order to recruit the pathogens classification purely relied on the molecular myco taxonomic characterization based on fungal ITS DNA sequencing and its phylogenetic interpretations. The current revolutions in molecular biology have provided advanced techniques in myco taxonomy. Molecular methods exploit the naturally occurring variations in the DNA. In eukaryotes, the ribosomal DNA (rDNA) found in the nuclear genome in general consists of tandem repeats of three RNA genes which undergoes transcription as a single unit and code for the 18S, 5.8S, and 28S subunits of the RNA [8], (Figure 1). The internal transcribed spacer (ITS) region of the nuclear ribosomal DNA is the unique DNA barcoding site for molecular identification of fungi. Analysis of DNA sequences from rRNA genes and the ITS region have been used in studies of phylogenetic relationships and evolution of a wide range of organisms. The gold standard for fungal ITS sequence based classification rely on the concept of phylogenetic recognition of species. This systematic approach is commonly used with conserved large or small subunit of rDNA across taxonomically diverse fungi [9,10]. The inclusion of taxonomically sundry ITS sequences into a single alignment are hectic because of considerable amounts of sequence variation, normally only the highly conserved 5.8S region can be considered for phylogenetic interpretations. Specific ITS primers (ITS1 and ITS4) were used in PCR to amplify a portion of the 18S rRNA gene, the ITS1 and ITS2 regions. Variation within the 18S rDNA and ITS1 region was interpreted viz sequence analysis and by Volume 4 Issue 5 2017