ERF4 affects fruit ripening by acting as a JAZ interactor between ethylene and jasmonic acid hormone signaling pathways

The regulation of apple(Malus domestica)fruit texture during ripening is complex and a fundamental determinant of its commercial quality.In climacteric fruit,ripening-related processes are regulated by ethylene(ET),and jasmonate(JA)is also involved in the ethylene biosynthesis pathway,mainly through the transcription factor MYC2.However,the molecular genetic mechanism for fruit ripening processes between the JA and ET signaling pathways still needs to be elucidated.In order to explore how JA regulates apple fruit ripening through ERF4,we used’Gala’and’Ralls Janet’fruit at different developmental stages as experimental materials to determine the fruit firmness and related gene expression analysis.Meanwhile,we carried out different hormone treatments on’Gala’fruit at ripening stage.Here,we show that ERF4 is a core JA signaling hub protein JASMONATE ZIM-DOMAIN(JAZ)interactor that affects ethylene signaling pathways.During fruit development,ERF4 represses the expression of ACS1 and ACO1 by interacting with JAZ,as well as with the JA-activated transcription factor MYC2.Ripening is promoted in JAZ-suppressed apples.Thus,ERF4 acts as a molecular link between ethylene and JA hormone signals,and the natural variation of the ERF4Ethylene-responsive binding factor-associated amphiphilic repression(EAR)motif decreases repression of ethylene biosynthesis genes.

Effects of Nitrogen Application on Photosynthetic Characteristics and Nitrogen Use Efficiency in Wheat after Rice

In the present study, appropriate nitrogen(N) application mode in Jianghan Plain was explored by investigating the effects of different N applications on the photosynthetic characteristics of flag leaves and nitrogen use efficiency(NUE) in a wheat cultivar Zhengmai 9023. Nitrogen was top-dressed before sowing, before winter, and during the jointing stage, at different ratios:1:1:0(N1), 1:0:1(N2), 2:1:1(N3), 1:1:1(N4), and 0:0:1(N5), under the same amount of total N(180 kg/hm^2) during the growing season. No nitrogen fertilizer was used in the control(N0). Results showed that the SPAD values and photosynthetic rate(Pn) of different treatments in flag leaves increased initially and then decreased around the anthesis stage. The two indices in N1 and N5 treatments decreased rapidly after flowering, whereas those in N2, N3, and N4 treatments maintained at high levels for a long period after anthesis. Thus, reasonable nitrogen application could retard the decline of SPAD and Pn after anthesis.N4 and N1 treatments showed large dry matter accumulation. In decreasing order of crop yield, the treatments were: N4 >N1 >N3 >N5 >N2 >N0. The effective panicle number and grain number per spike of N2 were significantly lower than those of other treatments, and there was no significant difference among other treatments. No significant correlation was found between nitrogen application and 1 000-grain weight in this experiment. The nitrogen accumulation, agronomic efficiency of nitrogen fertilizer,nitrogen uptake and use efficiency of above-ground parts, nitrogen uptake and use efficiency of grain of N4 treatment were higher than those of other treatments, but the nitrogen harvest index of N4 was at a low level. In summary, N4 treatment is the most suitable nitrogen application mode in wheat after rice.

Spatiotemporal Dynamics of the Molecular Expression Pattern

Nerve regeneration in adult mammalian spinal cord is poor because of the lack of intrinsic regeneration of neurons and extrinsic factors–the glial scar is triggered by injury and inhibits or promotes regeneration.Recent technological advances in spatial transcriptomics(ST)provide a unique opportunity to decipher most genes systematically throughout scar formation,which remains poorly understood.Here,we frst constructed the tissue-wide gene expression patterns of mouse spinal cords over the course of scar formation using ST after spinal cord injury from 32 samples.Locally,we profled gene expression gradients from the leading edge to the core of the scar areas to further understand the scar microenvironment,such as neurotransmitter disorders,activation of the pro-infammatory response,neurotoxic saturated lipids,angiogenesis,obstructed axon extension,and extracellular structure re-organization.In addition,we described 21 cell transcriptional states during scar formation and delineated the origins,functional diversity,and possible trajectories of subpopulations of fbroblasts,glia,and immune cells.Specifcally,we found some regulators in special cell types,such as Thbs1 and Col1a2 in macrophages,CD36 and Postn in fbroblasts,Plxnb2 and Nxpe3 in microglia,Clu in astrocytes,and CD74 in oligodendrocytes.Furthermore,salvianolic acid B,a blood–brain barrier permeation and CD36 inhibitor,was administered after surgery and found to remedy fbrosis.Subsequently,we described the extent of the scar boundary and profled the bidirectional ligand-receptor interactions at the neighboring cluster boundary,contributing to maintain scar architecture during gliosis and fbrosis,and found that GPR37L1_PSAP,and GPR37_PSAP were the most signifcant gene-pairs among microglia,fbroblasts,and astrocytes.Last,we quantifed the fraction of scar-resident cells and proposed four possible phases of scar formation:macrophage infltration,proliferation and diferentiation of scar-resident cells,scar emergence,and scar stationary.Together,these profles delineated the spatial heterogeneity of the scar,confrmed the previous concepts about scar architecture,provided some new clues for scar formation,and served as a valuable resource for the treatment of central nervous system injury.