Increasingly amplified stimulation mediated by TaNAC69‐B is crucial for the leaf senescence in wheat

Abstract

SUMMARY Leaf senescence involves massive multidimensional alterations, such as nutrient redistribution, and is closely related to crop yield and quality. No apical meristem, Arabidopsis transcription activation factor, and Cup‐shaped cotyledon (NAC)‐type transcription factors integrate various signals and modulate an enormous number of target genes to ensure the appropriate progression of leaf senescence. However, few leaf senescence‐related NACs have been functionally characterized in wheat. Based on our previous RNA‐sequencing (RNA‐seq) data, we focused on a NAC family member, TaNAC69‐B, which is increasingly expressed during leaf senescence in wheat. Overexpression of TaNAC69‐B led to precocious leaf senescence in wheat and Arabidopsis, and affected several agricultural traits in transgenic wheat. Moreover, impaired expression of TaNAC69‐B by virus‐induced gene silencing retarded the leaf senescence in wheat. By RNA‐seq and quantitative real‐time polymerase chain reaction analysis, we confirmed that some abscisic acid (ABA) biosynthesis genes, including AAO3 and its ortholog in wheat, TraesCS2B02G270600 (TaAO3‐B), were elevated by the overexpression of TaNAC69‐B. Consistently, we observed more severe ABA‐induced leaf senescence in TaNAC69‐B‐OE wheat and Arabidopsis plants. Furthermore, we determined that TaNAC69‐B bound to the NAC binding site core (CGT) on the promoter regions of AAO3 and TaAO3‐B. Moreover, we confirmed elevated ABA levels in TaNAC69‐B‐OE wheat lines. Although TaNAC69‐B shares 39.83% identity (amino acid) with AtNAP, TaNAC69‐B did not completely restore the delayed leaf senescence in the atnap mutant. Collectively, our results revealed a positive feedback loop, consisting of TaNAC69‐B, ABA biosynthesis and leaf senescence, that is essential for the regulation of leaf senescence in wheat.

Association of Temperature and Humidity with COVID-19 Transmission in Punjab, Pakistan

“…Numerous other studies also find the same results (Dadbakhsh et al, 2017;Gómez-Acebo et al, 2013;Macfarlane, 1977). Another study by (Li et al 2019) exposed that both hot and cold weather conditions adversatively affect respiratory infections. Kim et al (2016) increased temperature is linked with the decreased risk of cardiovascular diseases.…”

Wheat VQ Motif-Containing Protein VQ25-A Facilitates Leaf Senescence via the Abscisic Acid Pathway

“…Many ABA-related TFs, including AtNAP, OsNAC2, SlNAP2, and GhNAP, play vital roles in the regulation of leaf senescence [ 11 , 52 , 53 , 54 ]. Recently, TaNAC69-B promotes leaf senescence by affecting ABA levels, suggesting that ABA-associated fine-tuning at the transcriptional level is important for the modulation of leaf senescence in wheat [ 55 ]. Notably, we detected higher ABA levels in TaVQ25 - A -OE Arabidopsis lines than that in Col-0.…”