First Report of Rust Caused by Pucciniastrum guttatum on Galium sp From Pakistan.

Galium L. belongs to the Rubaceae family and comprises about 400 species, distributed mainly in temperate regions. Traditionally, Galium has been used as a medicinal plant by people with lymph cancer, fever, hypertension, insomnia, jaundice, leukemia, swellings, and wounds. In Pakistan, this genus is represented by 24 species that are sold in local markets because of their ethno-botanical uses. Some of these medicinal plants are traded in national herb markets of various cities in Pakistan, thus playing an important role in improving the socioeconomic conditions of the country (Ahmad and Javed 2007). This economically important plant is under the influence of various pathogens, among which is rust fungi caused by Pucciniastrum G.H. Otth. The genus Pucciniastrum, belonging to Pucciniasteraceae, was first established by Otth (1861) and currently contains approximately 30 species (Cummins and Hiratsuka 2003; Hiratsuka 1958). Only four of these species have been reported from Pakistan (Ahmad et al. 1997). Pucciniastrum guttatum (J. Schröt.) Hyl., Jørst. & Nannf is a common species that was previously named Caeoma galii Link, Melampsora galii G. Winter, M. guttata J. Schröt., Thekopsora galii (G. Winter) De Toni, and T. guttata (J. Schröt.) P. Syd. & Syd, and is often referred to as T. guttata in literature. (http://www.indexfungorum.org/names/Names.asp). During an exploration of the rust diversity in the Battagram District, Khyber Pakhtunkhwa, Pakistan (34.41°N, 73.1°E), in October 2014, wild Galium plants were found infected with the uredinial state of rust fungi on large area. The initial symptoms of the disease appeared as yellow circular spots on leaves that gradually changed to brown, spreading to whole leaf surface. The following morphological features were consistently observed: uredinia hypophyllous, small, rounded, brown, scattered; urediniospores globose to subglobose, light brown to hyaline, 14 to 18 × 16 to 23 μm; wall 0.5 to 1.5 μm thick, echinulate, germ pore obscure. DNA was extracted and the nuclear ribosomal large subunit (28S) was amplified according to the protocol outlined by Aime (2006). A BLASTn search (http://www.ncbi.nlm.nih.gov) showed that the 28S region shared 99% identity (842/845 bp) to three other published T. guttatum accessions (KJ716345 to 47 and AF426231 from an unknown location), with 100% query cover. The resulting sequence was deposited in GenBank (accession no. KX254357). Both morphological and molecular characteristics indicated that this species was P. guttatum, making this a first report of this pathogen in Pakistan. This fungus has been observed previously on Cruciata glabra in Poland, and on Galium spp. in various countries of Asia, Europe, the United States, and Madeira Islands (http://nt.ars-grin.gov/fungaldatabases/fungushost/fungushost.cfm). To the best of our knowledge, there are no other reports of this fungus on any other host within the country. The specimen has been vouchered in the both LAH Herbarium, Department of Botany, University of the Punjab, Lahore, Pakistan (LAH AM100051) and Arthur Herbarium, Purdue University, Indiana, U.S.A. (N11943). © The American Phytopathological Society.