Ectopic expression of GmNF-YA8 in Arabidopsis delays flowering via modulating the expression of gibberellic acid biosynthesis- and flowering-related genes and promotes lateral root emergence in low phosphorus conditions

Abstract

NUCLEAR FACTOR Y subunit alpha (NF-YA), together with NF-YB and NF-YC, regulates plant growth and development, as well as plant responses to biotic and abiotic stresses. Although extensive studies have examined the functions of NF-YAs in Arabidopsis thaliana, the roles of NF- YAs in Glycinme max are poorly understood. In this study, we identified a phosphorus (P) starvation-responsive NF-YA8 in soybean. The expression of GmNF-YA8 is induced by low P or low nitrogen in leaves, but not by potassium or iron starvation, respectively. GmNF-YA8 is localized in the nucleus and plasma membrane. Ectopic expression of GmNF-YA8 inhibits plant growth and delayed flowering in Arabidopsis. Exogenous application of gibberellic acid (GA) rescues the delayed flowering phenotype in Arabidopsis overexpressing GmNF-YA8 lines GmNF-YA8OE-05 and GmNF-YA8OE-20. Moreover, quantitative real time PCR (qRT-PCR) verified that overexpression of GmNF-YA8 downregulates GA20ox2 and GA3ox2 expression, but upregulates GA2ox2 and GA2ox3 that encode enzymes, which inactive bioactive GAs. Consistent with the late flowering phenotype of Arabidopsis trangenic lines that overexpress GmNF-YA8, the transcript levels of flowering-promoting genes AP1, CO, LFY, and SOC1 are reduced. In addition, overexpression of GmNF-YA8 promotes the emergence of lateral root (LR) primordium from epidermis rather than the initiation of LR in low P, and increases the LR density in low nitrogen. Our results provide insights into the roles of GmNF-YA8.

Soybean PHR1-regulated low phosphorus-responsiveGmRALF22increases uptake of phosphate via stimulatingGmPTs expression

“…After five days of growth, the number of lateral roots in Arabidopsis thaliana was quantified using a stereoscopic microscope (Evidengt, Germany). After capturing images of the samples using a Nikon D300s digital camera, the length of the primary root was quantified with ImageJ software (Ou et al .,2022).…”

“…The sterilized seeds were evenly planted in clean and moist quartz sand, and grown in growth room (25 ℃, light 16 h/ dark for 8 h) for 4 days. The uniform seedlings were transplanted into nutrient solution containing 500 μM phosphate (HP) or 5 μM phosphate (LP) (Ou et al, 2022). The nutrient solution was changed every seven days.…”

“…After five days of growth, the number of lateral roots in Arabidopsis thaliana was quantified using a stereoscopic microscope (Evidengt, Germany). After capturing images of the samples using a Nikon D300s digital camera, the length of the primary root was quantified with ImageJ software (Ou et al,2022) subtilis RIK1285 (Tang et al,2022). The transformed B. subtilis RIK1285 were cultured until the OD600 reach to 0.6, thus the bacteria were inoculated into soybean roots grown in LP for one week, and the empty vector B. subtilis was set up as control.…”

“…Given that soybean GmPHR1 (Glyma.19G167500) is a MYB transcription factor, which is up-regulated under low P conditions (Li et al, 2022), and Arabidopsis AtRALF1 is regulated by AtPHR1 (Tang et al, 2022). We thus hypothesized that soybean GmPHR1 may directly modulate the transcription of GmRALF22.…”

Arabidopsis Transcription Factor WRKY45 Confers Cadmium Tolerance via ActivatingPCS1andPCS2Expression

“…After sterilization, the seeds were sowed on half strength Murashige and Skoog (1/2 MS) media with 0.8% sucrose and 1% Phytagel (Sigma-Aldrich) and kept the plates in the dark at 4 °C for 2 days for stratification treatment. The seeds are then placed in a growth chamber with a thermocycle of 22 ℃/20 ℃ and a photoperiod of 16 h light/8 h dark, with a light intensity of 100 μmol -2 s -1 as described (Ou et al, 2022).…”