GmbZIP1 negatively regulates ABA-induced inhibition of nodulation by targeting GmENOD40–1 in soybean

Abstract

Background Abscisic acid (ABA) plays an important role in plant growth and adaptation through the ABA signaling pathway. The ABA-responsive element binding (AREB/ABF) family transcriptional factors are central regulators that integrate ABA signaling with various signaling pathways. It has long been known that ABA inhibits rhizobial infection and nodule formation in legumes, but the underlying molecular mechanisms remain elusive. Results Here, we show that nodulation is very sensitive to ABA and exogenous ABA dramatically inhibits rhizobial infection and nodule formation in soybean. In addition, we proved that GmbZIP1, an AREB/ABF transcription factor, is a major regulator in both nodulation and plant response to ABA in soybean. GmbZIP1 was specifically expressed during nodule formation and development. Overexpression of GmbZIP1 resulted in reduced rhizobial infection and decreased nodule number. Furthermore, GmbZIP1 is responsive to ABA, and ectopic overexpression of GmbZIP1 increased sensitivity of Arabidopsis plants to ABA during seed germination and postgerminative growth, and conferred enhanced drought tolerance of plants. Remarkably, we found that GmbZIP1 directly binds to the promoter of GmENOD40–1, a marker gene for nodule formation, to repress its expression. Conclusion Our results identified GmbZIP1 as a node regulator that integrates ABA signaling with nodulation signaling to negatively regulate nodule formation.

Overexpression of Terpenoid Biosynthesis Genes Modifies Root Growth and Nodulation in Soybean (Glycine max)

“…For example, NFR1 and NFR5 are major nodulation signaling genes in legumes that interact with Nod factors [ 58 , 59 , 60 , 61 , 62 ]. Many studies showed that the interaction of Nod factor receptors (NFRs) with Nod factors is fundamental for early nodule gene expression and nodule organogenesis [ 6 , 63 , 64 , 65 , 66 , 67 , 68 ]. Furthermore, Nodule inception transcription factors, GmNINa and GmNINb , regulate nodule organogenesis and infection thread development [ 55 , 69 , 70 ].…”

A Potential Role of Coumestrol in Soybean Leaf Senescence and Its Interaction With Phytohormones

“…Additionally, Lee et al (2012) reported the accumulation of coumestrol in root nodules. Moreover, recently, Xu et al (2021) reported that the reduction of root nodulation and rhizobial infection upon exogenous ABA application is related to the reduction of isoflavonoid compounds, including coumestrol. As indicated in Figure 3B , the yellow color that appeared throughout the leaf caused by coumestrol application looked similar to the changes that appear in soybean leaves when naturally aged.…”

“…Additionally, Lee et al (2012) reported the accumulation of coumestrol in root nodules. Moreover, recently Xu et al (2021) reported the reduction of root nodulation and rhizobial infection upon exogenous. Future investigations into the role of coumestrol in senescence, root development, and disease resistance can provide new insights into the roles of this important secondary metabolite.…”

Genome-Wide Identification Reveals the Potential Functions of the bZIP Gene Family in Common Bean (Phaseolus vulgaris) in Response to Salt Stress During the Sprouting Stage

“…Members of the bZIP transcription factor family, such as ABRE-binding factor and ABA-insensitive five (AREB/ ABF/ABI5) members, which responses to stress in Arabidopsis (Yoshida et al 2015), rice (O. sativa L.) (Yoshida et al 2010), and soybean (G. max L.) (Xu et al 2021) might regulate stress responses through the ABA signal way, but few study had been reported in common bean. Cloning of IbbZIP1 in sweet potatoes indicated that there might have been the same relationships between the ABA content and salt stress as the transgenic Arabidopsis (Chen et al 2019).…”