Expression and characterization of a barley phosphatidylinositol transfer protein structurally homologous to the yeast Sec14p protein

Genome-wide identification of the Sec14 gene family and the response to salt and drought stress in soybean (Glycine max)

BACKGROUND

The Sec14 domain is an ancient lipid-binding domain that evolved from yeast Sec14p and performs complex lipid-mediated regulatory functions in subcellular organelles and intracellular traffic. The Sec14 family is characterized by a highly conserved Sec14 domain, and is ubiquitously expressed in all eukaryotic cells and has diverse functions. However, the number and characteristics of Sec14 homologous genes in soybean, as well as their potential roles, remain understudied.

RESULTS

In this study, we identified 77 Sec14 genes in the soybean genome that were unevenly distributed across 19 chromosomes. Based on the classification method used for Arabidopsis Sec14 members, GmSec14s can be categorized into three classes: GmPITP1 to GmPITP37, GmSFH1 to GmSFH25, and GmPATL1 to GmPATL15. Structural analysis of the GmSec14 genes revealed that the SFH subfamily contained more introns than the other subfamilies. A total of 10 conserved protein motifs were detected within GmSec14 proteins, with each subfamily possessing unique motifs. Two tandem duplications and 73 segmental duplications were identified among the GmSec14 genes. Additionally, a large number of cis-acting elements, particularly those related to plant hormones, were abundant in the promoter regions of the GmSec14 genes. Tissue expression analysis of the GmSec14 genes indicated that they exhibited distinct tissue-specific expression patterns. In response to salt stress, multiple genes were found to be either upregulated or downregulated. In contrast, the majority of genes were downregulated under drought stress conditions. Notably, 12 GmSec14 genes exhibited significant alterations in expression following salt or drought stress, suggesting a potential role for these genes in stress response mechanisms. Furthermore, the protein interaction network and miRNA regulation associated with GmSec14s were predicted to elucidate the potential functions of GmSec14 members.

CONCLUSIONS

This study provides a systematic and comprehensive examination of the Sec14 gene family in soybean, which will facilitate further functional research into their roles in response to salt and drought tolerance.

Lipid Profile of Larix cajanderi Mayr in Adaptation to Natural Conditions in the Cryolithozone

The prevalence of coniferous trees in the forest landscapes of northeastern Siberia is conditioned by their high frost resistance. The Kajander larch (Larix cajanderi Mayr), which can survive under natural conditions (down to -60 °C) in the cryolithozone of Yakutia, is the dominant forest-forming species. We hypothesise that our study using HPTLC-UV/Vis/FLD, TLC-GC/FID, and GC-MS methods of seasonal features of the lipid profile of Kajander larch tissues will bring us closer to understanding the mechanisms of participation of lipid components in the adaptation of this valuable tree species to the cold climate of the cryolithozone. Rare delta5-unsaturated polymethylene-interrupted fatty acids (∆5-UPIFA) were identified in the fatty acids (FAs) of L. cajanderi shoots, including 18:2(Δ5.9) (taxoleic), 18:3(Δ5.9.12) (pinolenic), and 18:4(Δ5.9.12.15) (coniferonic). It was found that the content of ∆5-UPIFA in L. cajanderi shoots markedly increased (1.5-fold, representing up to 23.9% of sum FAs) during the autumnal transition of trees to dormancy. It was observed that the ranges of low temperatures experienced during the prolonged winter period primarily determined the structural diversity of membrane lipids and their constituent FAs during the cold adaptation of L. cajanderi. The results obtained can be used for the selection of molecular markers of cold tolerance in woody plants, including fruit trees.

Identification of two QTLs for web blotch resistance in peanut (Arachis hypogaea L.) based on BSA-seq

BACKGROUND

Peanut (Arachis hypogaea L.) is a globally important oilseed and cash crop. Web blotch is one of the most important peanut foliar diseases, causing severe yield losses worldwide.

RESULTS

In this study, an F6 population was used to identify quantitative trait loci (QTLs) for peanut web blotch resistance, based on bulked segregant analysis (BSA). Kompetitive Allele-Specific PCR (KASP) markers were developed and used to further narrow QTL intervals and detect candidate genes. Two major QTLs, qWBRA05 and qWBRA08 were identified, spanning physical intervals of 465.75 Kb and 434.83 Kb, and explaining percentages of phenotypic variation (PVE) of 8.79% and 15.09%, respectively. Moreover, two KASP markers were developed within the QTL interval effectively distinguished between web blotch resistance and web blotch susceptible materials.

CONCLUSIONS

The QTLs identified and two molecular markers closely linked to web blotch resistance were developed within the QTL interval, which are potentially valuable in peanut breeding.

Changes in Polar Lipid Composition in Balsam Fir during Seasonal Cold Acclimation and Relationship to Needle Abscission

Needle abscission in balsam fir has been linked to both cold acclimation and changes in lipid composition. The overall objective of this research is to uncover lipid changes in balsam fir during cold acclimation and link those changes with postharvest abscission. Branches were collected monthly from September to December and were assessed for cold tolerance via membrane leakage and chlorophyll fluorescence changes at -5, -15, -25, -35, and -45 °C. Lipids were extracted and analyzed using mass spectrometry while postharvest needle abscission was determined gravimetrically. Cold tolerance and needle retention each significantly (p < 0.001) improved throughout autumn in balsam fir. There were concurrent increases in DGDG, PC, PG, PE, and PA throughout autumn as well as a decrease in MGDG. Those same lipids were strongly related to cold tolerance, though MGDG had the strongest relationship (R2 = 55.0% and 42.7% from membrane injury and chlorophyll fluorescence, respectively). There was a similar, albeit weaker, relationship between MGDG:DGDG and needle retention (R2 = 24.3%). Generally, a decrease in MGDG:DGDG ratio resulted in better cold tolerance and higher needle retention in balsam fir, possibly due to increased membrane stability. This study confirms the degree of cold acclimation in Nova Scotian balsam fir and presents practical significance to industry by identifying the timing of peak needle retention. It is suggested that MGDG:DGDG might be a beneficial tool for screening balsam fir genotypes with higher needle retention characteristics.

Characterization of SEC14 family in wheat and the function of TaSEC14-7B in salt stress tolerance

Phospholipids are important components of plant biofilms and signal transduction. They are divided into glycerophospholipids and sphingolipids. Phosphatidylinositol (PI) is an intracellular glycerophospholipid. SEC14s are PI transporter proteins that are widely presented in eukaryotic. They take part in membrane transportation, inositol phosphate metabolism and adversity stress response. To date, systematic analysis of the SEC14 gene family in wheat, especially the function of SEC14 in salt stress tolerance has not been reported. In this study, 106 SEC14 family members have been identified in wheat. Then, a salt inducible Sec14 family member TaSEC14-7B was selected for further functional study in response to salt stress. Expression analysis demonstrated TaSEC14-7B was induced by NaCl, PEG treatment and localized both in the cell membrane and nucleus. TaSEC14-7B over-expressing Arabidopsis increased salt stress tolerance. Under salt stress, the transgenic plants displayed higher germination rate, longer primary root length, more soluble sugar accumulation, higher antioxidant enzyme activity and lower oxidative damage than the wild type plants. Also, at the presence of NaCl stress, the expression level of ABF4, P5CS, PLC4 and AtPLC7 genes was higher in TaSEC14 transgenic Arabidopsis than in the wild type ones. All these results lay a foundation for further study of Sec14 in wheat.

Identification and Expression Analysis of Phosphatidylinositol Transfer Proteins Genes in Rice

The family of phosphatidylinositol transfer proteins (PITPs) is able to bind specific lipids to carry out various biological functions throughout different stages of plant life. But the function of PITPs in rice plant is unclear. In this study, 30 PITPs were identified from rice genome, which showed differences in physicochemical properties, gene structure, conservation domains, and subcellular localization. The promoter region of the OsPITPs genes included at least one type of hormone response element, such as methyl jasmonate (Me JA) and salicylic acid (SA). Furthermore, the expression level of OsML-1, OsSEC14-3, OsSEC14-4, OsSEC14-15, and OsSEC14-19 genes were significantly affected by infection of rice blast fungus Magnaporthe oryzae. Based on these findings, it is possible that OsPITPs may be involved in rice innate immunity in response to M. oryzae infection through the Me JA and SA pathway.

Chloroplast-localized PITP7 is essential for plant growth and photosynthetic function in Arabidopsis

Recent studies of chloroplast-localized Sec14-like protein (CPSFL1, also known as phosphatidylinositol transfer protein 7, PITP7) showed that CPSFL1 is necessary for photoautotropic growth and chloroplast vesicle formation in Arabidopsis (Arabidopsis thaliana). Here, we investigated the functional roles of CPSFL1/PITP7 using two A. thaliana mutants carrying a putative null allele (pitp7-1) and a weak allele (pitp7-2), respectively. PITP7 transcripts were undetectable in pitp7-1 and less abundant in pitp7-2 than in the wild-type (WT). The severity of mutant phenotypes, such as plant developmental abnormalities, levels of plastoquinone-9 (PQ-9) and chlorophylls, photosynthetic protein complexes, and photosynthetic performance, were well related to PITP7 transcript levels. The pitp7-1 mutation was seedling lethal and was associated with significantly lower levels of PQ-9 and major photosynthetic proteins. pitp7-2 plants showed greater susceptibility to high-intensity light stress than the WT, attributable to defects in nonphotochemical quenching and photosynthetic electron transport. PITP7 is specifically bound to phosphatidylinositol phosphates (PIPs) in lipid-binding assays in vitro, and the point mutations R82, H125, E162, or K233 reduced the binding affinity of PITP7 to PIPs. Further, constitutive expression of PITP7^H125Q or PITP7^E162K in pitp7-1 homozygous plants restored autotrophic growth in soil but without fully complementing the mutant phenotypes. Consistent with a previous study, our results demonstrate that PITP7 is essential for plant development, particularly the accumulation of PQ-9 and photosynthetic complexes. We propose a possible role for PITP7 in membrane trafficking of hydrophobic ligands such as PQ-9 and carotenoids through chloroplast vesicle formation or direct binding involving PIPs.

Host extracts induce changes in the proteome of plant pathogen Fusarium proliferatum

Fusarium proliferatum is a polyphagous pathogenic fungus able to infect many crop plants worldwide. Differences in proteins accumulated were observed when maize- and asparagus-derived F. proliferatum strains were exposed to host extracts prepared from asparagus, maize, garlic, and pineapple tissues. Seventy-three unique proteins were up-regulated in extract-supplemented cultures compared to the controls. They were all identified using mass spectrometry and their putative functions were assigned. A major part of identified proteins was involved in sugar metabolism and basic metabolic processes. Increased accumulation of proteins typically associated with stress response (heat shock proteins, superoxide dismutases, and glutaredoxins) as well as others, putatively involved in signal transduction, suggests that some metabolites present in plant extracts may act as elicitors inducing similar reaction as the abiotic stress factors. As a case study, thirteen genes encoding the proteins induced by the extracts were identified in the genomes of diverse F. proliferatum strains using gene-specific DNA markers. Extract-induced changes in the pathogen's metabolism are putatively a result of differential gene expression regulation. Our findings suggest that host plant metabolites present in the extracts can cause biotic stress resulting in elevated accumulation of diverse set of proteins, including those associated with pathogen's stress response.