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High salinity is one of the major environmental stresses that plants encounter. Roots are the initial and direct organs to perceive the signal. However, how plant roots perceive and respond to salinity at the molecular and physiological levels is still poorly understood. Here, we report that ( ) plays a key role in primary root growth under salt stress conditions. Mutation of led to increased sensitivity to salt stress conditions, with strongly inhibited primary root growth and reduced survival rate in two mutant alleles. mutants accumulated greater Na and exhibited a greater Na /K ratio under NaCl treatment. In addition, more reactive oxygen species (ROS) accumulated in the mutants due to reduced ROS scavenging. NaCl treatment greatly suppressed the expression levels of , , , and , and suppressed root meristem activity in . GSH or auxin treatment greatly recovered the expression, auxin distribution and primary root growth in the mutants, suggesting ROS is a vital mediator between salt stress and auxin response. Our data support a model in which IAR4 integrates ROS and auxin pathways to modulate primary root growth under salinity stress conditions, by regulation of PIN-mediated auxin transport.

• The plant leaf surface is coated with a waterproof cuticle layer. Cuticle facing the stomatal pore surface needs to be sculpted to form outer cuticular ledge (OCL) after stomatal maturation for efficient gas exchange. Here, we characterized the roles of Arabidopsis GDSL lipase, Occlusion of Stomatal Pore 1 (OSP1), in wax biosynthesis and stomatal OCL formation. • OSP1 mutation results in significant reduction in leaf wax synthesis and occlusion of stomata, leading to increased epidermal permeability, decreased transpiration rate, and enhanced drought tolerance. We demonstrated that OSP1 activity is critical for its role in wax biosynthesis and stomatal function. In vitro enzymatic assays demonstrated that OSP1 possesses thioesterase activity, particularly on C22:0 and C26:0 acyl-CoAs. • Genetic interaction analyses with CER1 (ECERIFERUM 1), CER3 (ECERIFERUM 3) and MAH1 (Mid-chain Alkane Hydroxylase 1) in wax biosynthesis and stomatal OCL formation showed that OSP1 may act upstream of CER3 in wax biosynthesis, and implicate that wax composition percentage changes and keeping ketones in a lower level play roles, at least partially, in forming stomatal ledges. • Our findings provided insights into the molecular mechanism mediating wax biosynthesis and highlighted the link between wax biosynthesis and the process of stomatal OCL formation.

Background Brassica napus is an important vegetable oil source worldwide. Seed coat content is a complex quantitative trait that negatively correlates with the seed oil content in B. napus . Results Here we provide insights into the genetic basis of natural variation of seed coat content by transcriptome-wide association studies (TWAS) and genome-wide association studies (GWAS) using 382 B. napus accessions. By population transcriptomic analysis, we identify more than 700 genes and four gene modules that are significantly associated with seed coat content. We also characterize three reliable quantitative trait loci (QTLs) controlling seed coat content by GWAS. Combining TWAS and correlation networks of seed coat content-related gene modules, we find that BnaC07.CCR-LIKE ( CCRL ) and BnaTT8s play key roles in the determination of the trait by modulating lignin biosynthesis. By expression GWAS analysis, we identify a regulatory hotspot on chromosome A09, which is involved in controlling seed coat content through BnaC07.CCRL and BnaTT8s . We then predict the downstream genes regulated by BnaTT8s using multi-omics datasets. We further experimentally validate that BnaCCRL and BnaTT8 positively regulate seed coat content and lignin content. BnaCCRL represents a novel identified gene involved in seed coat development. Furthermore, we also predict the key genes regulating carbon allocation between phenylpropane compounds and oil during seed development in B. napus . Conclusions This study helps us to better understand the complex machinery of seed coat development and provides a genetic resource for genetic improvement of seed coat content in B. napus breeding.

Milk fat is the most important and energy-rich substance in milk, and its content and composition are important reference elements in the evaluation of milk quality. However, the current identification of valuable candidate genes affecting milk fat is limited. IlluminaPE150 was used to sequence bovine mammary epithelial cells (BMECs) with high and low milk fat rates (MFP), the weighted gene co-expression network (WGCNA) was used to analyze mRNA expression profile data in this study. As a result, a total of 10,310 genes were used to construct WGCNA, and the genes were classified into 18 modules. Among them, violet (r = 0.74), yellow (r = 0.75) and darkolivegreen (r =  − 0.79) modules were significantly associated with MFP, and 39, 181, 75 hub genes were identified, respectively. Combining enrichment analysis and differential genes (DEs), we screened five key candidate DEs related to lipid metabolism, namely PI4K2A, SLC16A1, ATP8A2, VEGFD and ID1, respectively. Relative to the small intestine, liver, kidney, heart, ovary and uterus, the gene expression of PI4K2A is the highest in mammary gland, and is significantly enriched in GO terms and pathways related to milk fat metabolism, such as monocarboxylic acid transport, phospholipid transport, phosphatidylinositol signaling system, inositol phosphate metabolism and MAPK signaling pathway. This study uses WGCNA to form an overall view of MFP, providing a theoretical basis for identifying potential pathways and hub genes that may be involved in milk fat synthesis.

Plants respond to adverse environment by initiating a series of signaling processes including activation of transcription factors that can regulate expression of arrays of genes for stress response and adaptation. NAC (NAM, ATAF, and CUC) is a plant specific transcription factor family with diverse roles in development and stress regulation. In this report, a stress-responsive NAC gene (SNAC2) isolated from upland rice IRA109 (Oryza sativa L. ssp japonica) was characterized for its role in stress tolerance. SNAC2 was proven to have transactivation and DNA-binding activities in yeast and the SNAC2-GFP fusion protein was localized in the rice nuclei. Northern blot and SNAC2 promoter activity analyses suggest that SNAC2 gene was induced by drought, salinity, cold, wounding, and abscisic acid (ABA) treatment. The SNAC2 gene was over-expressed in japonica rice Zhonghua 11 to test the effect on improving stress tolerance. More than 50% of the transgenic plants remained vigorous when all WT plants died after severe cold stress (4-8°C for 5 days). The transgenic plants had higher cell membrane stability than wild type during the cold stress. The transgenic rice had significantly higher germination and growth rate than WT under high salinity conditions. Over-expression of SNAC2 can also improve the tolerance to PEG treatment. In addition, the SNAC2-overexpressing plants showed significantly increased sensitivity to ABA. DNA chip profiling analysis of transgenic plants revealed many up-regulated genes related to stress response and adaptation such as peroxidase, ornithine aminotransferase, heavy metal-associated protein, sodium/hydrogen exchanger, heat shock protein, GDSL-like lipase, and phenylalanine ammonia lyase. Interestingly, none of the up-regulated genes in the SNAC2-overexpressing plants matched the genes up-regulated in the transgenic plants over-expressing other stress responsive NAC genes reported previously. These data suggest SNAC2 is a novel stress responsive NAC transcription factor that possesses potential utility in improving stress tolerance of rice.

The continuing rise in atmospheric carbon dioxide concentrations suppresses the development of stomatal pores, and thus gas exchange, in plant leaves on a global scale; now, a framework of mechanisms by which carbon dioxide represses development has been identified. Control of plant stomatal development The continuing rise in atmospheric CO 2 levels is suppressing the development of stomatal pores in plant leaves on a global scale. This, combined with the increasing scarcity of water for agriculture, can significantly affect plant carbon assimilation, heat stress and water-use efficiency. Julian Schroeder and colleagues investigate the genes and mechanisms through which CO 2 controls development of the stomatal pores that plants use to regulate gas exchange in leaves. They identify a framework of mechanisms: at high CO 2 levels, extracellular signalling and carbonic anhydrase regulate a novel protease called CRSP and the pro-peptide EPF2; this in turn represses stomatal development. Environmental stimuli, including elevated carbon dioxide levels, regulate stomatal development 1 , 2 , 3 ; however, the key mechanisms mediating the perception and relay of the CO 2 signal to the stomatal development machinery remain elusive. To adapt CO 2 intake to water loss, plants regulate the development of stomatal gas exchange pores in the aerial epidermis. A diverse range of plant species show a decrease in stomatal density in response to the continuing rise in atmospheric CO 2 (ref. 4 ). To date, one mutant that exhibits deregulation of this CO 2 -controlled stomatal development response, hic (which is defective in cell-wall wax biosynthesis, ref. 5 ), has been identified. Here we show that recently isolated Arabidopsis thaliana β-carbonic anhydrase double mutants ( ca1   ca4 ) 6 exhibit an inversion in their response to elevated CO 2 , showing increased stomatal development at elevated CO 2 levels. We characterized the mechanisms mediating this response and identified an extracellular signalling pathway involved in the regulation of CO 2 -controlled stomatal development by carbonic anhydrases. RNA-seq analyses of transcripts show that the extracellular pro-peptide-encoding gene EPIDERMAL PATTERNING FACTOR 2 ( EPF2 ) 7 , 8 , but not EPF1 (ref. 9 ), is induced in wild-type leaves but not in ca1 ca4 mutant leaves at elevated CO 2 levels. Moreover, EPF2 is essential for CO 2 control of stomatal development. Using cell-wall proteomic analyses and CO 2 -dependent transcript analyses, we identified a novel CO 2 -induced extracellular protease, CRSP (CO 2 RESPONSE SECRETED PROTEASE), as a mediator of CO 2 -controlled stomatal development. Our results identify mechanisms and genes that function in the repression of stomatal development in leaves during atmospheric CO 2 elevation, including the carbonic-anhydrase-encoding genes CA1 and CA4 and the secreted protease CRSP, which cleaves the pro-peptide EPF2, in turn repressing stomatal development. Elucidation of these mechanisms advances the understanding of how plants perceive and relay the elevated CO 2 signal and provides a framework to guide future research into how environmental challenges can modulate gas exchange in plants.

The plant hormone abscisic acid (ABA) is produced in response to abiotic stresses and mediates stomatal closure in response to drought via recently identified ABA receptors (pyrabactin resistance/regulatory component of ABA receptor; PYR/RCAR). SLAC1 encodes a central guard cell S-type anion channel that mediates ABA-induced stomatal closure. Coexpression of the calcium-dependent protein kinase 21 (CPK21), CPK23, or the Open Stomata 1 kinase (OST1) activates SLAC1 anion currents. However, reconstitution of ABA activation of any plant ion channel has not yet been attained. Whether the known core ABA signaling components are sufficient for ABA activation of SLAC1 anion channels or whether additional components are required remains unknown. The Ca ²⁺-dependent protein kinase CPK6 is known to function in vivo in ABA-induced stomatal closure. Here we show that CPK6 robustly activates SLAC1-mediated currents and phosphorylates the SLAC1 N terminus. A phosphorylation site (S59) in SLAC1, crucial for CPK6 activation, was identified. The group A PP2Cs ABI1, ABI2, and PP2CA down-regulated CPK6-mediated SLAC1 activity in oocytes. Unexpectedly, ABI1 directly dephosphorylated the N terminus of SLAC1, indicating an alternate branched early ABA signaling core in which ABI1 targets SLAC1 directly (down-regulation). Furthermore, here we have successfully reconstituted ABA-induced activation of SLAC1 channels in oocytes using the ABA receptor pyrabactin resistant 1 (PYR1) and PP2C phosphatases with two alternate signaling cores including either CPK6 or OST1. Point mutations in ABI1 disrupting PYR1–ABI1 interaction abolished ABA signal transduction. Moreover, by addition of CPK6, a functional ABA signal transduction core from ABA receptors to ion channel activation was reconstituted without a SnRK2 kinase.

The Wnt family features conserved glycoproteins that play roles in tissue regeneration, animal development and cell proliferation and differentiation. For its functional diversity and importance, this family has been studied in several species, but not in the Bovinae. Herein we identified 19 Wnt genes in cattle, and seven other species of Bovinae, and described their corresponding protein properties. Phylogenetic analysis clustered the 149 Wnt proteins in Bovinae, and 38 Wnt proteins from the human and mouse into 12 major clades. Wnt genes from the same subfamilies shared similar protein motif compositions and exon–intron patterns. Chromosomal distribution and collinearity analysis revealed that they were conservative in cattle and five species of Bovinae. RNA-seq data analysis indicated that Wnt genes exhibited tissue-specific expression in cattle. qPCR analysis revealed a unique expression pattern of each gene during bovine adipocytes differentiation. Finally, the comprehensive analysis indicated that Wnt2B may regulate adipose differentiation by activating FZD5 , which is worthy of further study. Our study presents the first genome-wide study of the Wnt gene family in Bovinae, and lays the foundation for further functional characterization of this family in bovine adipocytes differentiation.

Abiotic stresses such as drought cause a reduction of plant growth and loss of crop yield. Stomatal aperture controls CO 2 uptake and water loss to the atmosphere, thus playing important roles in both the yield gain and drought tolerance of crops. Here, a rice homologue of SRO (similar to RCD one), termed OsSRO1c, was identified as a direct target gene of SNAC1 (stress-responsive NAC 1) involved in the regulation of stomatal aperture and oxidative response. SNAC1 could bind to the promoter of OsSRO1c and activate the expression of OsSRO1c. OsSRO1c was induced in guard cells by drought stress. The loss-of-function mutant of OsSRO1c showed increased stomatal aperture and sensitivity to drought, and faster water loss compared with the wild-type plant, whereas OsSRO1c overexpression led to decreased stomatal aperture and reduced water loss. Interestingly, OsSRO1c-overexpressing rice showed increased sensitivity to oxidative stress. Expression of DST, a reported zinc finger gene negatively regulating H 2 O 2 -induced stomatal closure, and the activity of H 2 O 2 -scavening related enzymes were significantly suppressed, and H 2 O 2 in guard cells was accumulated in the overexpression lines. OsSRO1c interacted with various stress-related regulatory and functional proteins, and some of the OsSRO1c-interacting proteins are predicted to be involved in the control of stomatal aperture and oxidative stress tolerance. The results suggest that OsSRO1c has dual roles in drought and oxidative stress tolerance of rice by promoting stomatal closure and H 2 O 2 accumulation through a novel pathway involving regulators SNAC1 and DST.

Diacylglycerol acyltransferases (DGATs) play a key role in plant triacylglycerol (TAG) biosynthesis. Two type 1 and 2 DGATs from soybean were characterized for their functions in TAG biosynthesis and physiological roles. GmDGAT1A is highly expressed in seeds while GmDGAT2D is mainly expressed in flower tissues. They showed different expression patterns in response to biotic and abiotic stresses. GmDGAT2D was up-regulated by cold and heat stress and ABA signaling and repressed by insect biting and jasmonate, whereas GmDGAT1A show fewer responses. Both GmDGAT1A and GmDGAT2D were localized to the endoplasmic reticulum and complemented the TAG deficiency of a yeast mutant H1246. GmDGAT2D -transgenic hairy roots synthesized more 18:2- or 18:1-TAG, whereas GmDGAT1A prefers to use 18:3-acyl CoA for TAG synthesis. Overexpression of both GmDGAT s in Arabidopsis seeds enhanced the TAG production; GmDGAT2D promoted 18:2-TAG in wild-type but enhanced 18:1-TAG production in rod1 mutant seeds, with a decreased 18:3-TAG. However, GmDGAT1A enhanced 18:3-TAG and reduced 20:1-TAG contents. The different substrate preferences of two DGATs may confer diverse fatty acid profiles in soybean oils. While GmDGAT1A may play a role in usual seed TAG production and GmDGAT2D is also involved in usual TAG biosynthesis in other tissues in responses to environmental and hormonal cues.