RNA Sequencing-Associated Study Identifies GmDRR1 as Positively Regulating the Establishment of Symbiosis in Soybean

Abstract

In soybean (Glycine max)-rhizobium interactions, the type III secretion system (T3SS) of rhizobium plays a key role in regulating host specificity. However, the lack of information on the role of T3SS in signaling networks limits our understanding of symbiosis. Here, we conducted an RNA sequencing analysis of three soybean chromosome segment substituted lines, one female parent and two derived lines with different chromosome-substituted segments of wild soybean and opposite nodulation patterns. By analyzing chromosome-linked differentially expressed genes in the substituted segments and quantitative trait loci (QTL)-assisted selection in the substituted-segment region, genes that may respond to type III effectors to mediate plant immunity–related signaling were identified. To narrow down the number of candidate genes, QTL assistant was used to identify the candidate region consistent with the substituted segments. Furthermore, one candidate gene, GmDRR1, was identified in the substituted segment. To investigate the role of GmDRR1 in symbiosis establishment, GmDRR1-overexpression and RNA interference soybean lines were constructed. The nodule number increased in the former compared with wild-type soybean. Additionally, the T3SS-regulated effectors appeared to interact with the GmDDR1 signaling pathway. This finding will allow the detection of T3SS-regulated effectors involved in legume-rhizobium interactions.

Mapping quantitative trait loci related to nodule number in soybean (Glycine max (L.) Merr.) in response to the Sinorhizobium (Ensifer) fredii HH103 NopT type III effector

“…Plants were grown in sterile vermiculite in a greenhouse at 25°C with a 12-h light/12-h dark cycle. The B&D medium with trace nitrogen was used as the nutrient medium (Shi et al 2020). At the Vc stage (i.e.…”

Detection of type III effector‐induced transcription factors that regulate phytohormone content during symbiosis establishment in soybean

“…The TruSeq Stranded mRNA Library Prep Kit from Illumina was used to create PolyA + libraries. The mRNA sequencing was carried out on the Illumina HiSeq 4000 PE 150 platform (Shi et al, 2020). This study's transcriptome raw sequencing data have been submitted to the NCBI (http://www.ncbi.nlm.nih.gov/) database as individual BioProjects: PRJNA854816.…”

“…Magenta jars were superposed, connecting via a cotton band (Shi et al, 2020). The upper part of each Magenta jar was filled with vermiculite for soybean growth (one plant per jar), and the bottom part was filled with B&D medium (Broughton and Dilworth medium) containing 0.005 mM KNO 3 (Shi et al, 2020).…”

“…Magenta jars were superposed, connecting via a cotton band (Shi et al, 2020). The upper part of each Magenta jar was filled with vermiculite for soybean growth (one plant per jar), and the bottom part was filled with B&D medium (Broughton and Dilworth medium) containing 0.005 mM KNO 3 (Shi et al, 2020). One soybean seed per Magenta jar was planted in the vermiculite after sterilization by immersion in chlorine gas for 16 h. After the seeds were planted, the soybean growth was monitored in a plant‐growth chamber at 25°C with a 16 h/8 h (light/dark) photoperiod.…”

“…A negative impact on the nodule number of soybean cultivar Suinong 14 inoculated with NopAA mutant has also been found. A mutation in the gene encoding NopAA resulted in a decrease in the nodule number of soybeans, and a similar effect of RhcN was also found (Shi et al, 2020; Zou et al, 2021). RhcN is an enzyme that catalyzes the hydrolysis of ATP and all type III effectors were blocked following a mutation in the gene encoding RhcN (Viprey et al, 1998).…”