In: Sydowia 74, (2021): 107-119; ISSN 0082-0598, DOI 10.12905/0380.sydowia74-2021-0107, Published online on August 30, 2021

Genetic diversity and virulence of Iranian Bipolaris
sorokiniana isolates causing common root rot disease
of wheat

Zainab Zolfaghary, Mehdi Nasr Esfahan*, Khoshnood Nourollahi1 & Hamid Akbarzadeh

Plant Pathology Department, Faculty of Agriculture, Ilam University, Ilam, Iran
Plant Protection Research Department, Isfahan Agricultural and Natural Resources Research and Education Center
(AREEO), Isfahan, Iran
Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran

* E-mails: mne2011@gmail.com; m.nasr@aeero.ic.ir

Zolfaghary Z., Esfahan M.N., Nourollahi K. & Akbarzadeh H. (2021) Genetic diversity and virulence of Iranian Bipolaris sorokiniana
isolates causing common root rot disease of wheat. – Sydowia 74: 107–119.
Wheat, Triticum aestivum L., is an important and strategic crop worldwide. In recent times, wheat crops in Iran are seriously
affected by common root and crown rot disease (CRCR), caused by Bipolaris sorokiniana. A survey was conducted during the
2016–2017 growing seasons in 50 wheat fields. A total of 48 B. sorokiniana isolates were collected from infected root and crown
tissues, a month before maturity of the wheat plants. The isolates were subjected to virulence assays, and morphological, phylogenetic
and genetic diversity analyses. The virulence of ten random isolates was confirmed on wheat cv. ‘Parsi’ under greenhouse
conditions. For phylogenetic studies, the nucleus ITS region was sequenced in three random isolates, B4 (Zarin shahr), P1 and P5
(Baraan-e-Jonubi). To evaluate the genetic diversity of B. sorokiniana isolates, after DNA extraction, ten pairs of simple sequence
repeat (SSR) primer were used. The results of the virulence assays showed that all the isolates are pathogenic in various degrees,
causing 41–100 % disease severity, which were not directly correlated with geographic region. Morphological and phylogenic
studies of the isolates confirmed B. sorokiniana as the causal agent of the root and crown rot disease. In total, the ten SSR primer
pairs produced 16 distinct polymorphic bands. The mean polymorphic information content (PIC) was 0.716, marker index (MI)
3.467, and Shannon index (I) 0.497. BS096 and BS070 primers indicated the best efficiency in showing genetic diversity between
different B. sorokiniana isolates. A cluster analysis with NTSYS software was developed using UPGMA method and Jaccard’s
similarity matrix formation, with a coefficient of 89 %. Cluster analysis based on amplification patterns showed that the classified
groups were not correlated with geographical regions. The results of this study showed that SSR markers, with the polymorphism
percent of the primers varying from 50–100 %, at an average of 73.33 %, are a reliable marker system for detecting a high
level of polymorphism to study the genetic variation of B. sorokiniana isolates and are meaningful for developing strategies to
prevent and control wheat root rot.

Keywords: ITS region, phylogeny, SSR, Triticum aestivum, UPGMA.