The Sinorhizobium fredii HH103 type III secretion system effector NopC blocks nodulation with Lotus japonicus Gifu

Description

Results GunA from S. fredii HH103 shows cellulase activity and is secreted through the T3SS in response to the inducer flavonoid genistein. Interestingly, at the beggining of the symbiotic process, GunA was partially responsible for the induction of the expression of the soybean GmPR1 gene, a gene used as a marker for plant defense responses. However, GunAwas also detected in soybean and cowpea developed nodules. Finally, nodulation assays indicate that GunA is beneficial for symbiosis with soybean but detrimental with cowpea. Conclusion Secretion of GunA through the S. fredii HH103 T3SS clearly and differentially impacts the symbiotic performance of this strain with soybean and cowpea. GunA, or its cellulase activity, is recognised by soybean root cells very early in the symbiotic process but, curiously, its secretion can also be detected in mature nodules. This suggests different symbiotic roles at different symbiotic stages that need to be further elucidated

Abstract

Unión Europea. Ministerio de Economía y Competitividad. BIO2016-78409-R

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