Search Results (3)

Soybean is crucial to food processing and agricultural output. However, pests and diseases can easily impact soybeans, reducing their production. Soybean cyst nematode (SCN) is a soilborne pathogen that has a large geographic range, a long lifespan, and the potential to inflict substantial harm to the soybean industry. Persistent use of major resistance genes leads to a progressive loss of resistance; therefore, continuous identification of new soybean strains and genes is essential for continued sustainable soybean production. In this research, the SCN-resistant and SCN-sensitive germplasm DN-L10 and Heinong 37 were inoculated with SCN 3. After stress treatment, the stressed roots were collected for RNA-Seq analysis. The sequencing results screened out the differentially expressed gene GmbHLH18. The GmbHLH18 gene was cloned, and the overexpression vector pCAMBIA3300-GmbHLH18 was constructed. Agrobacterium infected soybean hairy roots and genetically modified the roots of DN50 soybeans, and transgenic root seedlings were obtained. The transgenically identified root seedlings were transplanted in soil infested with SCN 3, and resistance to root nematodes was determined by magenta staining. The secondary and tertiary structures of the protein, phosphorylation sites, as well as the hydrophilicity related to the GmbHLH18 gene were analyzed. Subsequently, the recombinant subcellular localization vector pCAMBIA1302-GmbHLH18 was employed. Agrobacterium was injected into tobacco leaves, and organelle-specific expression was observed. Finally, stress resistance-related indexes of the roots of overexpressing plants and WT plants under SCN 3 stress were measured. The results showed that overexpression and subcellular localization vectors were successfully constructed and transformed into Agrobacterium K599 and GV3101, respectively. The encoded protein had 1149 amino acids, a molecular weight of 95.76 kDa, an isoelectric point of 5.04, 60 phosphorylation sites, a tertiary structure of a-helix (36.39%), random coil (53.40%), extended chain (8.64%), and corner (1.57%), and was hydrophilic. The protein that the gene encoded was a nuclear-localized protein, according to the results of subcellular localization analysis. Moreover, the Agrobacterium-induced hairy root test revealed that the number of overexpressed pCAMBIA3300-GmbHLH18 transgenic roots in the unit area of DN50 was substantially lower than in the control group, which at first suggested that the gene had partial resistance to SCN 3. Stress resistance-related indexes suggest that the contents of POD, SOD, and proline in the overexpressing root significantly increase after SCN 3 stress, demonstrating that this gene can enhance the plant’s resistance to the SCN 3 pathogen. Future research could focus on further elucidating the molecular mechanism underlying the gene’s resistance to SCN 3 and exploring its potential application in breeding soybean varieties with enhanced resistance. Full article

Phytophthora root rot is a devastating disease of soybean caused by Phytophthora sojae. However, the resistance mechanism is not yet clear. Our previous studies have shown that GmAP2 enhances sensitivity to P. sojae in soybean, and GmMYB78 is downregulated in the transcriptome analysis of GmAP2-overexpressing transgenic hairy roots. Here, GmMYB78 was significantly induced by P. sojae in susceptible soybean, and the overexpressing of GmMYB78 enhanced sensitivity to the pathogen, while silencing GmMYB78 enhances resistance to P. sojae, indicating that GmMYB78 is a negative regulator of P. sojae. Moreover, the jasmonic acid (JA) content and JA synthesis gene GmAOS1 was highly upregulated in GmMYB78-silencing roots and highly downregulated in overexpressing ones, suggesting that GmMYB78 could respond to P. sojae through the JA signaling pathway. Furthermore, the expression of several pathogenesis-related genes was significantly lower in GmMYB78-overexpressing roots and higher in GmMYB78-silencing ones. Additionally, we screened and identified the upstream regulator GmbHLH122 and downstream target gene GmbZIP25 of GmMYB78. GmbHLH122 was highly induced by P. sojae and could inhibit GmMYB78 expression in resistant soybean, and GmMYB78 was highly expressed to activate downstream target gene GmbZIP25 transcription in susceptible soybean. In conclusion, our data reveal that GmMYB78 triggers soybean sensitivity to P. sojae by inhibiting the JA signaling pathway and the expression of pathogenesis-related genes or through the effects of the GmbHLH122-GmMYB78-GmbZIP25 cascade pathway. Full article

Soybean [Glycine max (L.) Merr.] is an important oil crop that provides valuable resources for human consumption, animal feed, and biofuel. Through the transcriptome analysis in our previous study, GmLecRlk (Glyma.07G005700) was identified as a salt-responsive candidate gene in soybean. In this study, qRT-PCR analysis showed that the GmLecRlk gene expression level was significantly induced by salt stress and highly expressed in soybean roots. The pCAMBIA3300-GmLecRlk construct was generated and introduced into the soybean genome by Agrobacterium rhizogenes. Compared with the wild type (WT), GmLecRlk overexpressing (GmLecRlk-ox) soybean lines had significantly enhanced fresh weight, proline (Pro) content, and catalase (CAT) activity, and reduced malondialdehyde (MDA) and H₂O₂ content under salt stress. These results show that GmLecRlk gene enhanced ROS scavenging ability in response to salt stress in soybean. Meanwhile, we demonstrated that GmLecRlk gene also conferred soybean salt tolerance when it was overexpressed alone in soybean hairy root. Furthermore, the combination of RNA-seq and qRT-PCR analysis was used to determine that GmLecRlk improves the salt tolerance of soybean by upregulating GmERF3, GmbHLH30, and GmDREB2 and downregulating GmGH3.6, GmPUB8, and GmLAMP1. Our research reveals a new mechanism of salt resistance in soybean, which exposes a novel avenue for the cultivation of salt-resistant varieties. Full article