7EAU

SIB1, an effector of Colletotrichum orbiculare

Summary for 7EAU

• Entry DOI: 10.2210/pdb7eau/pdb
• Descriptor: SIN1 (1 entity in total)
• Functional Keywords: structure from xplor-nih, toxin
• Biological source: Colletotrichum orbiculare (strain 104-T / ATCC 96160 / CBS 514.97 / LARS 414 / MAFF 240422) (Cucumber anthracnose fungus, Colletotrichum lagenarium)
• Total number of polymer chains: 1
• Total formula weight: 5046.59

Authors

Mori, M.,Ohki, S.,Kurita, J. (deposition date: 2021-03-08, release date: 2021-11-03, Last modification date: 2023-06-14)

Primary citation

Zhang, R.,Isozumi, N.,Mori, M.,Okuta, R.,Singkaravanit-Ogawa, S.,Imamura, T.,Kurita, J.I.,Gan, P.,Shirasu, K.,Ohki, S.,Takano, Y.
Fungal effector SIB1 of Colletotrichum orbiculare has unique structural features and can suppress plant immunity in Nicotiana benthamiana.
J.Biol.Chem., 297:101370-101370, 2021

PubMed Abstract: Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection; however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N. benthamiana. The Agrobacterium-mediated transient expression of SIB1 or SIB2 increased the susceptibility of N. benthamiana to C. orbiculare, which suggested these effectors can suppress immune responses in N. benthamiana. The presence of SIB1 and SIB2 homologs was found to be limited to the genus Colletotrichum. SIB1 suppressed both (i) the generation of reactive oxygen species triggered by two different pathogen-associated molecular patterns, chitin and flg22, and (ii) the cell death response triggered by the Phytophthora infestans INF1 elicitin in N. benthamiana. We determined the NMR-based structure of SIB1 to obtain its structural insights. The three-dimensional structure of SIB1 comprises five β-strands, each containing three disulfide bonds. The overall conformation was found to be a cylindrical shape, such as the well-known antiparallel β-barrel structure. However, the β-strands were found to display a unique topology, one pair of these β-strands formed a parallel β-sheet. These results suggest that the effector SIB1 present in Colletotrichum fungi has unique structural features and can suppress pathogen-associated molecular pattern-triggered immunity in N. benthamiana.

PubMed: 34756891
DOI: 10.1016/j.jbc.2021.101370

Experimental method

SOLUTION NMR