ThSCSP_12: Novel Effector in <i>Tilletia horrida</i> That Induces Cell Death and Defense Responses in Non-Host Plants
The basidiomycete fungus <i>Tilletia horrida</i> causes rice kernel smut (RKS), a crucial disease afflicting hybrid-rice-growing areas worldwide, which results in significant economic losses. However, few studies have investigated the pathogenic mechanisms and functions of effectors in &...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-11-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/23/14752 |
| Summary: | The basidiomycete fungus <i>Tilletia horrida</i> causes rice kernel smut (RKS), a crucial disease afflicting hybrid-rice-growing areas worldwide, which results in significant economic losses. However, few studies have investigated the pathogenic mechanisms and functions of effectors in <i>T. horrida</i>. In this study, we found that the candidate effector ThSCSP_12 caused cell necrosis in the leaves of <i>Nicotiana benthamiana</i>. The predicted signal peptide (SP) of this protein has a secreting function, which is required for ThSCSP_12 to induce cell death. The 1- 189 amino acid (aa) sequences of ThSCSP_12 are sufficient to confer it the ability to trigger cell death in <i>N. benthamiana</i>. The expression of ThSCSP_12 was induced and up-regulated during <i>T. horrida</i> infection. In addition, we also found that ThSCSP_12 localized in both the cytoplasm and nucleus of plant cells and that nuclear localization of this protein is required to induce cell death. Furthermore, the ability of ThSCSP_12 to trigger cell death in <i>N. benthamiana</i> depends on the (RAR1) protein required for Mla12 resistance but not on the suppressor of the G2 allele of Skp1 (SGT1), heat shock protein 90 (HSP90), or somatic embryogenesis receptor-like kinase (SERK3). Crucially, however, ThSCSP_12 induced a defense response in <i>N. benthamiana</i> leaves; yet, the expression of multiple defense-related genes was suppressed in response to heterologous expression in host plants. To sum up, these results strongly suggest that ThSCSP_12 operates as an effector in <i>T. horrida</i>–host interactions. |
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| ISSN: | 1661-6596 1422-0067 |