• Abscisic acid (ABA) and jasmonic acid (JA) both inhibit seed germination, but their interactions during this process remain elusive. Here, we report the identification of a ‘SAPK10-bZIP72-AOC’ ...pathway, through which ABA promotes JA biosynthesis to synergistically inhibit rice seed germination.
• Using biochemical interaction and phosphorylation assays, we show that SAPK10 exhibits autophosphorylation activity on the 177th serine, which enables it to phosphorylate bZIP72 majorly on 71st serine. The SAPK10-dependent phosphorylation enhances bZIP72 protein stability as well as the DNA-binding ability to the G-box cis-element of AOC promoter, thereby elevating the AOC transcription and the endogenous concentration of JA.
• Blocking of JA biosynthesis significantly alleviated the ABA sensitivity on seed germination, suggesting that ABA-imposed inhibition partially relied on the elevated concentration of JA.
• Our findings shed a novel insight into the molecular networks of ABA–JA synergistic interaction during rice seed germination.
Premature leaf senescence significantly reduces rice yields. Despite identifying numerous factors influencing these processes, the intricate genetic regulatory networks governing leaf senescence ...demand further exploration. We report the characterization of a stably inherited, ethyl methanesulfonate(EMS)-induced rice mutant with wilted leaf tips from seedling till harvesting, designated lts2. This mutant exhibits dwarfism and early senescence at the leaf tips and margins from the seedling stage when compared to the wild type. Furthermore, lts2 displays a substantial decline in both photosynthetic activity and chlorophyll content. Transmission electron microscopy revealed the presence of numerous osmiophilic granules in chloroplast cells near the senescent leaf tips, indicative of advanced cellular senescence. There was also a significant accumulation of H2O2, alongside the up-regulation of senescence-associated genes within the leaf tissues. Genetic mapping situated lts2 between SSR markers Q1 and L12, covering a physical distance of approximately 212 kb in chr.1. No similar genes controlling a premature senescence leaf phenotype have been identified in the region, and subsequent DNA and bulk segregant analysis (BSA) sequencing analyses only identified a single nucleotide substitution (C-T) in the exon of LOC_Os01g35860. These findings position the lts2 mutant as a valuable genetic model for elucidating chlorophyll metabolism and for further functional analysis of the gene in rice.
Lateral branches such as shoot and panicle are determining factors and target traits for rice (Oryza sativa L.) yield improvement. Cytokinin promotes rice lateral branching; however, the mechanism ...underlying the fine-tuning of cytokinin homeostasis in rice branching remains largely unknown. Here, we report the map-based cloning of RICE LATERAL BRANCH (RLB) encoding a nuclear-localized, KNOX-type homeobox protein from a rice cytokinin-deficient mutant showing more tillers, sparser panicles, defected floret morphology as well as attenuated shoot regeneration from callus. RLB directly binds to the promoter and represses the transcription of OsCKX4, a cytokinin oxidase gene with high abundance in panicle branch meristem. OsCKX4 over-expression lines phenocopied rlb, which showed upregulated OsCKX4 levels. Meanwhile, RLB physically binds to Polycomb repressive complex 2 (PRC2) components OsEMF2b and co-localized with H3K27me3, a suppressing histone modification mediated by PRC2, in the OsCKX4 promoter. We proposed that RLB recruits PRC2 to the OsCKX4 promoter to epigenetically repress its transcription, which suppresses the catabolism of cytokinin, thereby promoting rice lateral branching. Moreover, antisense inhibition of OsCKX4 under the LOG promoter successfully increased panicle size and spikelet number per plant without affecting other major agronomic traits. This study provides insight into cytokinin homeostasis, lateral branching in plants, and also promising target genes for rice genetic improvement.
Serine carboxypeptidase (SCP) is one of the largest groups of enzymes catalyzing proteolysis for functional protein maturation. To date, little is known about the function of SCPs in rice. In this ...study, we present a comprehensive analysis of the gene structure and expression profile of 59 rice SCPs. SCP46 is dominantly expressed in developing seeds, particularly in embryo, endosperm and aleurone layers, and could be induced by ABA. Functional characterization revealed that knock-down of SCP46 resulted in smaller grain size and enhanced seed germination. Furthermore, scp46 seed germination became less sensitive to the ABA inhibition than the Wild-type did; suggesting SCP46 is involved in ABA signaling. As indicated by RNA-seq and qRT-PCR analysis, numerous grain filling and seed dormancy related genes, such as SP, VP1 and AGPs were down-regulated in scp46. Yeast-two-hybrid assay also showed that SCP46 interacts with another ABA-inducible protein DI19-1. Taken together, we suggested that SCP46 is a master regulator of grain filling and seed germination, possibly via participating in the ABA signaling. The results of this study shed novel light into the roles of SCPs in rice.
Long-term structural health monitoring (SHM) has become an important tool to ensure the safety of infrastructures. However, determining methods to extract valuable information from large amounts of ...data from SHM systems for effective identification of damage still remains a major challenge. This paper provides a novel effective method for structural damage detection by introduction of space and time windows in the traditional principal component analysis (PCA) technique. Numerical results with a planar beam model demonstrate that, due to the presence of space and time windows, the proposed double-window PCA method (DWPCA) has a higher sensitivity for damage identification than the previous method moving PCA (MPCA), which combines only time windows with PCA. Further studies indicate that the developed approach, as compared to the MPCA method, has a higher resolution in localizing damage by space windows and also in quantitative evaluation of damage severity. Finally, a finite-element model of a practical bridge is used to prove that the proposed DWPCA method has greater sensitivity for damage detection than traditional methods and potential for applications in practical engineering.
The "
to
" initiative in China focuses on adapting
rice varieties from the northeast to the unique photoperiod and temperature conditions of lower latitudes. While breeders can select varieties for ...their adaptability, the sensitivity to light and temperature often complicates and prolongs the process. Addressing the challenge of cultivating high-yield, superior-quality
rice over expanded latitudinal ranges swiftly, in the face of these sensitivities, is critical. Our approach harnesses the CRISPR-Cas9 technology to edit the
gene in the premium northeastern
cultivars Jiyuanxiang 1 and Yinongxiang 12, which are distinguished by their exceptional grain quality-increased head rice rates, gel consistency, and reduced chalkiness and amylose content. Field trials showed that these new
mutants not only surpass the wild types in yield when grown at low latitudes but also retain the desirable traits of their progenitors. Additionally, we found that disabling
boosts the activity of
and
, postponing flowering by approximately one month in the
mutants. This research presents a viable strategy for the accelerated breeding of elite northeastern
rice by integrating genomic insights with gene-editing techniques suitable for low-latitude cultivation.
The role of miR-26a-5p expression in cardiac hypertrophy remains unclear. Herein, the effect of miR-26a-5p on cardiac hypertrophy was investigated using phenylephrine (PE)-induced cardiac hypertrophy ...in vitro and in a rat model of hypertension-induced hypertrophy in vivo.
The PE-induced cardiac hypertrophy models in vitro and vivo were established. To investigate the effect of miR-26a-5p activation on autophagy, the protein expression of autophagosome marker (LC3) and p62 was detected by western blot analysis. To explore the effect of miR-26a-5p activation on cardiac hypertrophy, the relative mRNA expression of cardiac hypertrophy related mark GSK3
was detected by qRT-PCR in vitro and vivo. In addition, immunofluorescence staining was used to detect cardiac hypertrophy related mark
-actinin. The cell surface area was measured by immunofluorescence staining. The direct target relationship between miR-26a-5p and GSK3
was confirmed by dual luciferase report.
MiR-26a-5p was highly expressed in PE-induced cardiac hypertrophy. MiR-26a-5p promoted LC3II and decreased p62 expression in PE-induced cardiac hypertrophy in the presence or absence of lysosomal inhibitor. Furthermore, miR-26a-5p significantly inhibited GSK3
expression in vitro and in vivo. Dual luciferase report results confirmed that miR-26a-5p could directly target GSK3
. GSK3
overexpression significantly reversed the expression of cardiac hypertrophy-related markers including ANP, ACTA1 and MYH7. Immunofluorescence staining results demonstrated that miR-26a-5p promoted cardiac hypertrophy related protein
-actinin expression, and increased cell surface area in vitro and in vivo.
Our study revealed that miR-26a-5p promotes myocardial cell autophagy activation and cardiac hypertrophy by regulating GSK3
, which needs further research.
Gibberellins (GAs) are diterpenoid phytohormones regulating various aspects of plant growth and development, such as internode elongation and seed germination. Although the GA biosynthesis pathways ...have been identified, the transcriptional regulatory network of GA homeostasis still remains elusive. Here, we report the functional characterization of a GA-inducible
in GA biosynthesis underpinning plant height and seed germination. Overexpression of
produced a typical GA-deficient phenotype with semi-dwarf and retarded seed germination. Meanwhile, the phenotypes could be rescued by exogenous GA
, suggesting that
is a key regulator of GA homeostasis. OsABF1 could directly suppress the transcription of green revolution gene
, thus reducing the endogenous GA level in rice. Moreover, OsABF1 interacts with and transcriptionally antagonizes to the polycomb repression complex component OsEMF2b, whose mutant showed as similar but more severe phenotype to
overexpression lines. It is suggested that OsABF1 recruits RRC2-mediated H3K27me3 deposition on the
promoter, thus epigenetically silencing
to maintain the GA homeostasis for growth and seed germination. These findings shed new insight into the functions of
and regulatory mechanism underlying GA homeostasis in rice.
Chilling stress seriously limits grain yield and quality worldwide. However, the genes and the underlying mechanisms that respond to chilling stress remain elusive. This study identified ABF1, a ...cold-induced transcription factor of the bZIP family. Disruption of
impaired chilling tolerance with increased ion leakage and reduced proline contents, while
over-expression lines exhibited the opposite tendency, suggesting that ABF1 positively regulated chilling tolerance in rice. Moreover, SnRK2 protein kinase SAPK10 could phosphorylate ABF1, and strengthen the DNA-binding ability of ABF1 to the G-box
-element of the promoter of
, a positive regulator of trehalose biosynthesis, consequently elevating the
transcription and the endogenous trehalose contents. Meanwhile, applying exogenous trehalose enhanced the chilling tolerance of
mutant lines. In summary, this study provides a novel pathway 'SAPK10-ABF1-
' involved in rice chilling tolerance through regulating trehalose homeostasis.
Dysfunction of the intestinal epithelial tight junction (TJ) barrier is known to have an important etiologic role in the pathophysiology of heat stroke. N-3 polyunsaturated fatty acids (PUFAs), ...including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a role in maintaining and protecting the TJ structure and function. This study is aimed at investigating whether n-3 PUFAs could alleviate heat stress-induced dysfunction of intestinal tight junction.
Human intestinal epithelial Caco-2 cells were pre-incubated with EPA, DHA or arachidonic acid (AA) and then exposed to heat stress. Transepithelial electrical resistance (TEER) and Horseradish Peroxidase (HRP) permeability were measured to analyze barrier integrity. Levels of TJ proteins, including occludin, ZO-1 and claudin-2, were analyzed by Western blot and localized by immunofluorescence microscopy. Messenger RNA levels were determined by quantitative real time polymerase chain reaction (Q-PCR). TJ morphology was observed by transmission electron microscopy.
EPA effectively attenuated the decrease in TEER and impairment of intestinal permeability in HRP flux induced by heat exposure. EPA significantly elevated the expression of occludin and ZO-1, while DHA was less effective and AA was not at all effective. The distortion and redistribution of TJ proteins, and disruption of morphology were also effectively prevented by pretreatment with EPA.
This study indicates for the first time that EPA is more potent than DHA in protecting against heat-induced permeability dysfunction and epithelial barrier damage of tight junction.
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