The biotrophy-associated secreted protein 4 (BAS4) participates in the transition of Magnaporthe oryzae from the biotrophic to the necrotrophic phase

Chunmei Wang; Yanfang Liu; Lin Liu; Yunfeng Wang; Jinlu Yan; Changmi Wang; Chengyun Li; Jing Yang

doi:10.1016/j.sjbs.2019.01.003

The biotrophy-associated secreted protein 4 (BAS4) participates in the transition of Magnaporthe oryzae from the biotrophic to the necrotrophic phase

Saudi J Biol Sci. 2019 May;26(4):795-807. doi: 10.1016/j.sjbs.2019.01.003. Epub 2019 Jan 8.

Authors

Chunmei Wang¹, Yanfang Liu^{1

2}, Lin Liu¹, Yunfeng Wang¹, Jinlu Yan¹, Changmi Wang¹, Chengyun Li¹, Jing Yang¹

Affiliations

¹ State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 65000, China.
² Quality Standard and Testing Technology Research Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China.

Abstract

The physiological and metabolic processes of host plants are manipulated and remodeled by phytopathogenic fungi during infection, revealed obvious signs of biotrophy of the hemibiotrophic pathogen. As we known that effector proteins play key roles in interaction of hemibiotrophic fungi and their host plants. BAS4 (biotrophy-associated secreted protein 4) is an EIHM (extrainvasive hyphal membrane) matrix protein that was highly expressed in infectious hyphae. In order to study whether BAS4 is involved in the transition of rice blast fungus from biotrophic to necrotrophic phase, The susceptible rice cultivar Lijiangxintuanheigu (LTH) that were pre-treated with prokaryotic expression product of BAS4 and then followed with inoculation of the blast strain, more serious blast disease symptom, more biomass such as sporulation and fungal relative growth, and lower expression level of pathogenicity-related genes appeared in lesion of the rice leaves than those of the PBS-pretreated-leaves followed with inoculation of the same blast strain, which demonstrating that BAS4 invitro changed rice defense system to facilitate infection of rice blast strain. And the susceptible rice cultivar (LTH) were inoculated withBAS4-overexpressed blast strain, we also found more serious blast disease symptom and more biomass also appeared in lesion of leaves inoculated with BAS4-overexpressed strain than those of leaves inoculated with the wild-type strain, and expression level of pathogenicity-related genes appeared lower in biotrophic phase and higher in necrotrophic phase of infection, indicating BAS4 maybe in vivo regulate defense system of rice to facilitate transition of biotrophic to necrotrophic phase. Our data demonstrates that BAS4 in vitro and in vivo participates in transition from the biotrophic to the necrotrophic phase of Magnaporthe oryzae.

Keywords: ATMT, agrobacterium tumefaciens-mediated transformation; BAS, biotrophy-associated secreted; BIC, biotrophic interfacial complex; Bgh, Blumeria graminis; DAB, diaminobenzidine; EIHM, extra-invasive hyphal membrane; Effector; GFP, green fluorescence protein; GST, glutathione-S-transferase; Hemibiotrophic fungi; IH, invasive hyphae; LTH, Lijiangxintuanheigu; M.oryzae, Magnaporthe oryzae; Magnaporthe oryzae; ORF, open reading frame; OsMPK12, rice mitogen-activated protein kinase 12; OsMPK6, rice mitogen-activated protein kinase 6; PBS, phosphate buffer saline; PCD, programmed cell death; PDA, potato dextrose agar; PR gene, pathogenicity related gene; ROS, reactive oxygen species; Rice; YLG, Yue Liang Gu; hpi, hours post inoculation.