Catálogo de publicaciones - revistas

<jats:p>Eukaryotic cells possess endomembrane organelles equipped with specific sets of proteins, lipids, and polysaccharides that are fundamental for realizing each organelle’s specific function and shape. A tightly regulated membrane trafficking system mediates the transportation and localization of these substances. Generally, the secretory/exocytic pathway is responsible for transporting cargo to the plasma membrane and/or the extracellular space. However, in the case of oil body cells in the liverwort <jats:italic>Marchantia polymorpha,</jats:italic> the oil body, a liverwort-unique organelle, is thought to be formed by secretory vesicle fusion through redirection of the secretory pathway inside the cell. Although their formation mechanism remains largely unclear, oil bodies exhibit a complex and bumpy surface structure. In this study, we isolated a mutant with spherical oil bodies through visual screening of mutants with abnormally shaped oil bodies. This mutant harbored a mutation in a coat protein complex I (COPI) subunit MpSEC28, and a similar effect on oil body morphology was also detected in knockdown mutants of other COPI subunits. Fluorescently tagged MpSEC28 was localized to the periphery of the Golgi apparatus together with other subunits, suggesting that it is involved in retrograde transport from and/or in the Golgi apparatus as a component of the COPI coat. The Mp<jats:italic>sec28</jats:italic> mutants also exhibited weakened stiffness of the thalli, suggesting impaired cell–cell adhesion and cell wall integrity. These findings suggest that the mechanism of cell wall biosynthesis is also involved in shaping the oil body in <jats:italic>M. polymorpha</jats:italic>, supporting the redirection of the secretory pathway inward the cell during oil body formation.</jats:p>

<jats:p>NAC proteins constitute one of the largest transcription factor families and are involved in regulation of plant development and stress responses. Our previous transcriptome analyses of tobacco revealed a significant increase in the expression of <jats:italic>NtNAC028</jats:italic> during leaf yellowing. In this study, we found that <jats:italic>NtNAC028</jats:italic> was rapidly upregulated in response to high salinity, dehydration, and abscisic acid (ABA) stresses, suggesting a vital role of this gene in abiotic stress response. <jats:italic>NtNAC028</jats:italic> loss-of-function tobacco plants generated <jats:italic>via</jats:italic> CRISPR-Cas9 showed delayed leaf senescence and increased tolerance to drought and salt stresses. Meanwhile <jats:italic>NtNAC028</jats:italic> overexpression led to precocious leaf senescence and hypersensitivity to abiotic stresses in <jats:italic>Arabidopsis</jats:italic>, indicating that <jats:italic>NtNAC028</jats:italic> functions as a positive regulator of natural leaf senescence and a negative regulator of stress tolerance. Furthermore, <jats:italic>NtNAC028</jats:italic>-overexpressing <jats:italic>Arabidopsis</jats:italic> plants showed lower antioxidant enzyme activities, higher reactive oxygen species (ROS), and H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> accumulation under high salinity, resulted in more severe oxidative damage after salt stress treatments. On the other hand, <jats:italic>NtNAC028</jats:italic> mutation in tobacco resulted in upregulated expression of ROS-scavenging and abiotic stress-related genes, higher antioxidant enzyme activities, and enhanced tolerance against abiotic stresses, suggesting that <jats:italic>NtNAC028</jats:italic> might act as a vital regulator for plant stress response likely by mediating ROS scavenging ability. Collectively, our results indicated that the <jats:italic>NtNAC028</jats:italic> plays a key regulatory role in leaf senescence and response to multiple abiotic stresses.</jats:p>

<jats:p>Globally, droughts are the most widespread climate factor impacting carbon (C) cycling. However, as the second-largest terrestrial C flux, the responses of soil respiration (Rs) to extreme droughts co-regulated by seasonal timing and PFT (plant functional type) are still not well understood. Here, a manipulative extreme-duration drought experiment (consecutive 30 days without rainfall) was designed to address the importance of drought timing (early-, mid-, or late growing season) for Rs and its components (heterotrophic respiration (Rh) and autotrophic respiration (Ra)) under three PFT treatments (two graminoids, two shrubs, and their combination). The results suggested that regardless of PFT, the mid-drought had the greatest negative effects while early-drought overall had little effect on Rh and its dominated Rs. However, PFT treatments had significant effects on Rh and Rs in response to the late drought, which was PFT-dependence: reduction in shrubs and combination but not in graminoids. Path analysis suggested that the decrease in Rs and Rh under droughts was through low soil water content induced reduction in MBC and GPP. These findings demonstrate that responses of Rs to droughts depend on seasonal timing and communities. Future droughts with different seasonal timing and induced shifts in plant structure would bring large uncertainty in predicting C dynamics under climate changes.</jats:p>

<jats:p>Wax coating is an important means to maintain fruit quality and extend fruit shelf life, especially for climacteric fruits, such as apples (<jats:italic>Malus domestica</jats:italic>). Here, we found that wax coating could inhibit ethylene production, chlorophyll degradation, and carotenoid synthesis, but the molecular mechanism remains unclear. The regulatory mechanism of wax coating on apple fruit ripening was determined by subjecting wax-treated apple fruits to transcriptome analysis. RNA-seq revealed that 1,137 and 1,398 genes were upregulated and downregulated, respectively. These differentially expressed genes (DEGs) were shown to be related to plant hormones, such as ethylene, auxin, abscisic acid, and gibberellin, as well as genes involved in chlorophyll degradation and carotenoid biosynthesis. Moreover, we found that some genes related to the wax synthesis process also showed differential expression after the wax coating treatment. Among the DEGs obtained from RNA-seq analysis, 15 were validated by quantitative RT-PCR, confirming the results from RNA-seq analysis. RNA-seq and qRT-PCR of pear (<jats:italic>Pyrus ussuriensis</jats:italic>) showed similar changes after wax treatment. Our data suggest that wax coating treatment inhibits fruit ripening through ethylene synthesis and signal transduction, chlorophyll metabolism, and carotenoid synthesis pathways and that waxing inhibits endogenous wax production. These results provide new insights into the inhibition of fruit ripening by wax coating.</jats:p>

<jats:p>Hydrogels have outstanding research and application prospects in the field of product design. Among them, the design and preparation of cellulose-based functional hydrogels derived from bamboo have attracted increasing research interest. Cellulose-based hydrogels not only have the skeleton function of hydrogels, but also retain excellent specificity, smart structural design, precise molecular recognition ability, and superior biocompatibility. Cellulose-based hydrogels show important application prospects in various fields, such as environmental protection, biomedicine, and energy. What’s more, they are potentially viable for application in food packaging and plant agriculture, such as fertilizers release and crop production. Recently, researchers have extracted cellulose from bamboo and generated a variety of cellulose-based functional hydrogels with excellent properties by various cross-linking methods. In addition, a variety of multifunctional hybrid cellulose-based hydrogels have been constructed by introducing functional components or combining them with other functional materials, thus expanding the breadth and depth of their applications. Herein, we elaborate on advances in the field of cellulose-based hydrogels and highlight their applications in food packaging and plant agriculture. Meanwhile, the existing problems and prospects are summarized. The review provides a reference for the further development of cellulose-based hydrogels.</jats:p>

<jats:p>Most rhodophytes synthesize semi-amylopectin as a storage polysaccharide, whereas some species in the most primitive class (Cyanidiophyceae) make glycogen. To know the roles of isoamylases in semi-amylopectin synthesis, we investigated the effects of <jats:italic>isoamylase</jats:italic> gene (<jats:italic>CMI294C</jats:italic> and <jats:italic>CMS197C</jats:italic>)-deficiencies on semi-amylopectin molecular structure and starch granule morphology in <jats:italic>Cyanidioschyzon merolae</jats:italic> (Cyanidiophyceae). Semi-amylopectin content in a <jats:italic>CMS197C</jats:italic>-disruption mutant (<jats:italic>ΔCMS197C</jats:italic>) was not significantly different from that in the control strain, while that in a <jats:italic>CMI294C</jats:italic>-disruption mutant (<jats:italic>ΔCMI294C</jats:italic>) was much lower than those in the control strain, suggesting that CMI294C is essential for semi-amylopectin synthesis. Scanning electron microscopy showed that the <jats:italic>ΔCMI294C</jats:italic> strain contained smaller starch granules, while the <jats:italic>ΔCMS197C</jats:italic> strain had normal size, but donut-shaped granules, unlike those of the control strain. Although the chain length distribution of starch from the control strain displayed a semi-amylopectin pattern with a peak around degree of polymerization (DP) 11–13, differences in chain length profiles revealed that the <jats:italic>ΔCMS197C</jats:italic> strain has more short chains (DP of 3 and 4) than the control strain, while the <jats:italic>ΔCMI294C</jats:italic> strain has more long chains (DP ≥12). These findings suggest that CMI294C-type isoamylase, which can debranch a wide range of chains, probably plays an important role in semi-amylopectin synthesis unique in the Rhodophyta.</jats:p>

<jats:p>Leaf rust of barley causes significant losses in crops of susceptible cultivars. Deploying host resistance is the most cost-effective and eco-sustainable strategy to protect the harvest. However, most known leaf rust resistance genes have been overcome by the pathogen due to the pathogen’s evolution and adaptation. The discovery of novel sources of genetic resistance is vital to keep fighting against pathogen evolution. In this study, we investigated the genetic basis of resistance in barley breeding line GID 5779743 (GID) from ICARDA, found to carry high levels of seedling resistance to prevalent Australian pathotypes of <jats:italic>Puccinia hordei</jats:italic>. Multipathotype tests, genotyping, and marker-trait associations revealed that the resistance in GID is conferred by two independent genes. The first gene, <jats:italic>Rph3</jats:italic>, was detected using a linked CAPS marker and QTL analysis. The second gene was detected by QTL analysis and mapped to the same location as that of the <jats:italic>Rph5</jats:italic> locus on the telomeric region of chromosome 3HS. The segregating ratio in F<jats:sub>2</jats:sub> (conforming to 9 resistant: 7 susceptible genetic ratio; <jats:italic>p</jats:italic> &amp;gt; 0.8) and F<jats:sub>3</jats:sub> (1 resistant: 8 segregating: 7 susceptible; <jats:italic>p</jats:italic> &amp;gt; 0.19) generations of the GID × Gus population, when challenged with pathotype 5477 P− (virulent on <jats:italic>Rph3</jats:italic> and <jats:italic>Rph5</jats:italic>) suggested the interaction of two genes in a complementary fashion. This study demonstrated that <jats:italic>Rph3</jats:italic> interacts with <jats:italic>Rph5</jats:italic> or an additional locus closely linked to <jats:italic>Rph5</jats:italic> (tentatively designated <jats:italic>RphGID</jats:italic>) in GID to produce an incompatible response when challenged with a pathotype virulent on <jats:italic>Rph3+Rph5</jats:italic>.</jats:p>

<jats:p>Heightening the resistance of plants to microbial infection is a widely concerned issue, especially for economical crops. Receptor-like proteins (RLPs), typically with tandem leucine-rich repeats (LRRs) domain, play a crucial role in mediating immune activation, being an indispensable constituent in the first layer of defense. Based on an analysis of orthologs among <jats:italic>Brassica rapa, Brassica oleracea</jats:italic>, and <jats:italic>Brassica napus</jats:italic> using <jats:italic>Arabidopsis thaliana</jats:italic> RLPs as a reference framework, we found that compared to <jats:italic>A. thaliana</jats:italic>, there were some obvious evolutionary diversities of RLPs among the three <jats:italic>Brassicaceae</jats:italic> species. <jats:italic>BnRLP</jats:italic> encoding genes were unevenly distributed on chromosomes, mainly on chrA01, chrA04, chrC03, chrC04, and chrC06. The orthologs of five <jats:italic>At</jats:italic>RLPs (<jats:italic>At</jats:italic>RLP3, <jats:italic>At</jats:italic>RLP10, <jats:italic>At</jats:italic>RLP17, <jats:italic>At</jats:italic>RLP44, and <jats:italic>At</jats:italic>RLP51) were highly conserved, but retrenchment and functional centralization occurred in <jats:italic>Brassicaceae</jats:italic> RLPs during evolution. The RLP proteins were clustered into 13 subgroups. Ten <jats:italic>BnRLPs</jats:italic> presented expression specificity between R and S when elicited by <jats:italic>Sclerotinia sclerotiorum</jats:italic>, which might be fabulous candidates for <jats:italic>S. sclerotiorum</jats:italic> resistance research.</jats:p>

<jats:p>Identification of marker trait association is a prerequisite for marker-assisted breeding. To find markers linked with traits under heat and drought stress in bread wheat (<jats:italic>Triticum aestivum</jats:italic> L.), we performed a genome-wide association study (GWAS). GWAS mapping panel used in this study consists of advanced breeding lines from the IARI stress breeding programme produced by pairwise and complex crosses. Phenotyping was done at multi locations namely New Delhi, Karnal, Indore, Jharkhand and Pune with augmented-RCBD design under different moisture and heat stress regimes, namely timely sown irrigated (IR), timely sown restricted irrigated (RI) and late sown (LS) conditions. Yield and its component traits, <jats:italic>viz</jats:italic>., Days to Heading (DH), Days to Maturity (DM), Normalized Difference Vegetation Index (NDVI), Chlorophyll Content (SPAD), Canopy temperature (CT), Plant Height (PH), Thousand grain weight (TGW), Grain weight per spike (GWPS), Plot Yield (PLTY) and Biomass (BMS) were phenotyped. Analysis of variance and descriptive statistics revealed significant differences among the studied traits. Genotyping was done using the 35k SNP Wheat Breeder's Genotyping Array. Population structure and diversity analysis using filtered 10,546 markers revealed two subpopulations with sufficient diversity. A large whole genome LD block size of 7.15 MB was obtained at half LD decay value. Genome-wide association search identified 57 unique markers associated with various traits across the locations. Twenty-three markers were identified to be stable, among them nine pleiotropic markers were also identified. <jats:italic>In silico</jats:italic> search of the identified markers against the IWGSC ref genome revealed the presence of a majority of the SNPs at or near the gene coding region. These SNPs can be used for marker-assisted transfer of genes/QTLs after validation to develop climate-resilient cultivars.</jats:p>

<jats:p>Potato is a temperate crop consumed globally as a staple food. High temperature negatively impacts the tuberization process, eventually affecting crop yield. DNA methylation plays an important role in various developmental and physiological processes in plants. It is a conserved epigenetic mark determined by the dynamic concurrent action of cytosine-5 DNA methyltransferases (<jats:italic>C5-MTases</jats:italic>) and demethylases (<jats:italic>DeMets</jats:italic>). However, <jats:italic>C5-MTases</jats:italic> and <jats:italic>DeMets</jats:italic> remain unidentified in potato, and their expression patterns are unknown under high temperatures. Here, we performed genome-wide analysis and identified 10 C5-MTases and 8 DeMets in potatoes. Analysis of their conserved motifs, gene structures, and phylogenetic analysis grouped <jats:italic>C5-MTases</jats:italic> into four subfamilies (<jats:italic>StMET, StCMT3, StDRM</jats:italic>, and <jats:italic>StDNMT2</jats:italic>) and <jats:italic>DeMets</jats:italic> into three subfamilies (<jats:italic>StROS, StDML</jats:italic>, and <jats:italic>StDME</jats:italic>). Promoter analysis showed the presence of multiple cis-regulatory elements involved in plant development, hormone, and stress response. Furthermore, expression dynamics of <jats:italic>C5-MTases</jats:italic> and <jats:italic>DeMets</jats:italic> were determined in the different tissues (leaf, flower, and stolon) of heat-sensitive (HS) and heat-tolerant (HT) genotypes under high temperature. qPCR results revealed that high temperature resulted in pronounced upregulation of <jats:italic>CMT</jats:italic> and <jats:italic>DRM</jats:italic> genes in the HT genotype. Likewise, demethylases showed strong upregulation in HT genotype as compared to HS genotype. Several positive (<jats:italic>StSP6A</jats:italic> and <jats:italic>StBEL5</jats:italic>) and negative (<jats:italic>StSP5G, StSUT4</jats:italic>, and <jats:italic>StRAP1</jats:italic>) regulators are involved in the potato tuberization. Expression analysis of these genes revealed that high temperature induces the expression of positive regulators in the leaf and stolon samples of HT genotype, possibly through active DNA demethylation and RNA-directed DNA methylation (RdDM) pathway components. Our findings lay a framework for understanding how epigenetic pathways synergistically or antagonistically regulate the tuberization process under high-temperature stress in potatoes. Uncovering such mechanisms will contribute to potato breeding for developing thermotolerant potato varieties.</jats:p>