European Journal of Plant Pathology

, Volume 145, Issue 2, pp 239–253 | Cite as

Genome-wide identification of the mildew resistance locus O (MLO) gene family in novel cereal model species Brachypodium distachyon



Powdery mildew (PM) is an important plant fungal disease that adversely affects a broad range of angiosperm species, including grass families such as wheat and barley. The MLO (powdery mildew locus O) protein acts as a negative regulator in PM-resistance. Loss-of-function mutation in MLO shows complete resistance to PM disease. In this study, for the first time we reported MLO gene family members in Brachypodium distachyon, model species for grass. 11 well-conserved BdMLO genes were identified on all five chromosomes with a scattered occurrence rather than clustered. The subcellular localization and topology analyses confirmed that all BdMLO proteins anchored to plasma membrane. The seven trans-membrane (TM) and calmodulin-binding domain (CaMBD) sites were well conserved. Amino acid composition showed that BdMLO proteins were leucine-rich (9.9–13.1 %) except BdMLO5 and BdMLO8, which were alanine-rich (10.0 %) and serine-rich (8.7 %), respectively. In silico functional dissection of cis-acting elements revealed that BdMLOs were associated with mainly hormonal, stress, light response and tissue-specific signaling pathways. Phylogenetic relations of BdMLOs within distinct plant species (Arabidopsis, barley, wheat, maize, rice, tomato, pea, pepper and peach) were evaluated. Also, digital expressions of BdMLOs in drought, cold and pathogen infection conditions revealed stress-responsive MLO genes. Phylogenetic and expression analyses provided preliminary evidence that BdMLO2 could be the best susceptibility gene which may play important role in PM resistance. It was concluded that identification and characterization of MLO gene members in Brachypodium will provide essential knowledge for studying full-scale functional analysis of these genes in grass species.


MLO gene Powdery mildew Brachypodium distachyon Resistance 


Compliance with ethical standards

This article does not contain any studies with human participants or animals performed by any of the authors.

Conflict of interest

Author1 declares that he has no conflict of interest. Author2 declares that he has no conflict of interest.

Supplementary material

10658_2015_833_MOESM1_ESM.xlsx (12 kb)
Online Resource 1 Functions of the cis-regulatory elements that found in the promoter regions of the BdMLO genes. (XLSX 11 kb)


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Copyright information

© Koninklijke Nederlandse Planteziektenkundige Vereniging 2015

Authors and Affiliations

  1. 1.Department of Biology, Faculty of Arts and ScienceFatih UniversityBuyukcekmeceTurkey

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