Abstract
Shoot branching is one of the most variable determinants of crop yield, and the signaling pathways of plant branches have become a hot research topic. As an important transcription factor in the B3 family, NGATHA1 (NGA1), plays an important role in regulating plant lateral organ development and hormone synthesis and transport, but few studies of the role of this gene in the regulation of plant growth and stress tolerance have been reported. In this study, the NGA1 gene was isolated from Medicago truncatula (Mt) and its function was characterized. The cis-acting elements upstream of the 5′ end of MtNGA1 and the expression pattern of MtNGA1 were analyzed, and the results indicated that the gene may act as a regulator of stress resistance. A plant expression vector was constructed and transgenic Arabidopsis plants were obtained. Transgenic Arabidopsis showed delayed flowering time and reduced branching phenotypes. Genes involved in the regulation of branching and flowering were differentially expressed in transgenic plants compared with wild-type plants. Furthermore, transgenic plants demonstrated strong tolerances to salt- and mannitol-induced stresses, which may be due to the upregulated expression of NCED3 (NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3) by the MtNGA1 gene. These results provide useful information for the exploration and genetic modification use of MtNGA1 in the future.
Highlights
The B3 superfamily consists of plant-specific transcription factors that are present in green algae, mosses [1], liverworts, ferns and gymnosperms, all of which are vascular plants
Based on the results of cis-acting element prediction analysis, M. truncatula samples under different abiotic stresses and abscisic acid (ABA) treatment conditions were harvested. quantitative RT-PCR (qRT-PCR) was performed, and the results showed that MtNGA1 was differentially expressed in different tissues
MAX and BRC can inhibit branching, and the qRT-PCR results showed that AtMAX1 and AtMAX2 as well as AtBRC1 and AtBRC2 were upregulated in the transgenic plants (Figure 6D)
Summary
The B3 superfamily consists of plant-specific transcription factors that are present in green algae, mosses [1], liverworts, ferns and gymnosperms, all of which are vascular plants. The B3 family plays a central role in plant life, and its members are characterized by the presence of B3 DNA-binding domains (DBDs) [4] This domain was initially named because it was the third basic domain to be discovered in the maize gene VP1 (VIVIPAROUS1) [5]. The B3 family has been investigated for its role in regulating pathways such as flower organ and leaf development, meristem division and differentiation, and the stress response. NGA proteins affect plant organ development and regulate hormone synthesis and transport and drought-stress tolerance pathways. Actmfroonmg tohtehBer Bfa3mfialimesiliyn tMra.ntrsucnricpatiuolna, Mfact7togr1s1f7r4o5m5 hMad. ttrhuenhcaigtuhleas.t homology with MtNGA1 (only 44.5%) (Figure 1B) This result may indicate that MtNGA1 plays a role distinct from other B3 family transcription factors from M. truncatula. Gm19g261300, Gm03g262200; Zea mays (Zm): Zm2g024948, Zm2g018485, Zm2g102059; Brachypodium distachyon (Bd): Bd3g51840, Bd5g19260, Bd4g25170, Bd4g42167
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