Expression of a NGATHA1 Gene from Medicago truncatula Delays Flowering Time and Enhances Stress Tolerance

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.

Genome Wide Identification and Annotation of NGATHA Transcription Factor Family in Crop Plants

“…They also examined the reduced shoot branching by analyzing the transcript levels of SMXL genes in the MtNGA1 overexpression lines to observe that the transcript levels of AtSMXL6, AtSMXL7, and AtSMXL8 were downregulated while the expression of AtMAX1/2, AtBRC1, and AtBRC2 were up-regulated. The repressed shoot branching in the transgenic lines provides important evidence that NGA not only influences ABA, but also regulates strigolactones [22].…”

“…Despite the limited literature available, NGA has also been involved in various stress responses [10,22]. Sato et al [10] overexpressed AtNGA1-GFP under the influence of the 35S promoter, examined the two-week old seedlings subjected to water stress under the confocal microscope and observed increased protein accumulation of AtNGA1-GFP under drought stress compared to the control conditions.…”

“…A similar pattern was seen in ABA-deficient mutants of Arabidopsis, where NGA induced AtNCED3 to synthesize ABA in response to stress. In addition, a study by Guo et al [22] showed that the overexpression of MtNGA1 from Medicago truncatula in A. thaliana exhibited increased tolerance to high salt stress. They also exhibited a reduction in the number of branches in the overexpressed lines along with delayed flowering, indicating the importance of NGA as key players in crucial aspects of plant development as well as stress responses.…”

QTL analysis of flowering‐related traits by specific length amplified fragment sequencing in melon

“…At present, some FT approximate genes have been found in many horticultural crops such as melon (Zhang & Zhang, 2020), ginkgo ( Ginkgo biloba L.) (Wang et al., 2019), and white lupin ( Lupinus albus L.) (Rychel et al., 2019). Besides the FT gene, TFL1 (Zhao et, al., 2018; Khanouki et al., 2020), NGATHA1 (Guo et, al., 2020), LFY (Qi et al., 2015), FLC (Kumar et al., 2016), and SOC1 (Liu et al., 2020) were also important genes that regulated flowering time. Ffn2.1 and Ffn2.2 were closely related to the first flower node in pepper ( Capsicum annuum L.) (Zhang et al., 2019).…”

“…It is also an essential marker of the transformation of plants from basic vegetative growth to reproductive growth. The flowering process of higher plants is regulated by external conditions such as light, temperature, moisture, and nutrition, as well as a complex network of flowering promotion and suppression genes (Guo et al., 2020; Khanouki & Millar. et al., 2020; Kumar et al., 2016; Lu et al., 2014; Qi et al., 2015; Zhao et al., 2018).…”