miR169c‐NFYA‐C‐ENOD40 modulates nitrogen inhibitory effects in soybean nodulation

Abstract

Summary Legume crops contribute a great portion of clean nitrogen (N) to agro‐ecosystems through symbiotic N2 fixation in the nodule; however, the nodulation is always inhibited by high N availability which is known as the N inhibitory effect through largely unknown mechanisms. We functionally investigated miR169c‐GmNFYA‐C‐GmENOD40 under multiple N conditions in soybean (Glycine max) (ENOD, Early Nodulin; NFYA, Nuclear Factor‐Y Subunit A). We elucidated their regulatory roles in soybean nodulation through analyzing expression patterns, micro–messenger RNA (miRNA–mRNA) interactions, phenotypes of transgenic soybean plants and genetic interactions. We found that miR169c expression was induced by high N, whereas its target GmNFYA‐C was preferentially expressed in nodules and induced by rhizobium inoculation. Overexpression of miR169c inhibited nodulation through targeting 3′‐UTR of GmNFYA‐C, whereas knockout miR169c through CRISPR‐cas9 promoted nodulation. However, overexpression of GmNFYA‐C promoted soybean nodulation through facilitating rhizobium infection and increasing the expression of symbiotic signaling gene GmENOD40. Besides, GmNFYA‐C directly induced the expression of GmENOD40. In addition, overexpression of GmNFYA‐C without the target site of miR169c partially attenuated the inhibitory effect of high N on soybean nodulation. We discovered a new regulatory pathway involving the miR169c‐NFYA‐C‐ENOD40 module that regulates soybean nodulation in response to N availability. This pathway provides substantial new insights into the mechanisms underlying the N inhibitory effect on nodulation.

Spatiotemporal changes in gibberellin content are required for soybean nodulation

“…We also investigated the response of critical nodulation genes to GA application. NIN is an early nodulation gene involved in both rhizobia infection and cortical cell division (Schauser et al ., 1999; Soyano et al ., 2013; Yoro et al ., 2014) and acts upstream of the early nodulin gene ENOD40 (Soyano et al ., 2013; Xu et al ., 2021). Treatments of 10 −6 M and 10 −4 M GA 3 significantly induced the expression of GmNIN1a , GmNIN2a , GmNIN2b , GmENOD40a , and GmENOD40b within 12 h of application (Fig.…”

Phosphate starvation responsive GmSPX5 mediates nodule growth through interaction with GmNF‐YC4 in soybean (Glycine max)

“…Among them, GmNF‐YC4 and GmNF‐YC3, homologs of AtNF‐YC4, were suggested to modulate C and N allocation (Li et al., 2015). Recently, GmNF‐YA10 has been suggested to regulate soybean nodulation through mediating GmENOD40 expression (Xu et al., 2020). In other legume species, several NF‐Y transcription factors have also been implicated as regulators of nodulation, including MtNF‐YA1 and MtNF‐YA2 in M. truncatula , LjNF‐YA1 in Lotus japonicu s , and PvNF‐YC1 in common bean (Hossain et al., 2016; Laloum et al., 2014; Mazziotta et al., 2013; Soyano et al., 2013).…”

QTL mapping of genes related to Nod factor signalling using recombinant inbred lines of soybean (Glycine max)

“…Nitrogen is one of the factors limiting soybean nodulation. Therefore, NRT1.2 may contribute to the nitrogen‐related inhibitory effect of miR169c‐NFYA‐C‐ENOD40 on soybean nodulation (Xu et al, 2021). Furthermore, NRT1 reportedly affects organogenesis and nodule functions in Lotus japonicus (Criscuolo et al, 2012).…”