Catálogo de publicaciones - revistas

<jats:title>SUMMARY</jats:title><jats:p>The biogenesis and differentiation (B&amp;D) of amyloplasts contributes to fruit flavor and color. Here, remodeling of starch granules, thylakoids and plastoglobules was observed during development and ripening in two kiwifruit (<jats:italic>Actinidia</jats:italic> spp.) cultivars – yellow‐fleshed ‘Hort16A’ and green‐fleshed ‘Hayward’. A protocol was developed to purify starch‐containing plastids with a high degree of intactness, and amyloplast B&amp;D was studied using label‐free‐based quantitative proteomic analyses in both cultivars. Over 3000 amyloplast‐localized proteins were identified, of which &gt;98% were quantified and defined as the kfALP (<jats:styled-content>k</jats:styled-content>iwi<jats:styled-content>f</jats:styled-content>ruit <jats:styled-content>a</jats:styled-content>my<jats:styled-content>l</jats:styled-content>oplast <jats:styled-content>p</jats:styled-content>roteome). The kfALP data were validated by Tandem‐Mass‐Tag (TMT) labeled proteomics in ‘Hort16A’. Analysis of the proteomic data across development and ripening revealed: 1) a conserved increase in the abundance of proteins participating in starch synthesis/degradation during both amyloplast B&amp;D; 2) up‐regulation of proteins for chlorophyll degradation and of plastoglobule‐localized proteins associated with chloroplast breakdown and plastoglobule formation during amyloplast differentiation; 3) constitutive expression of proteins involved in ATP supply and protein import during amyloplast B&amp;D. Interestingly, two different pathways of amyloplast B&amp;D were observed in the two cultivars. In ‘Hayward’, significant increases in abundance of photosynthetic‐ and tetrapyrrole metabolism‐related proteins were observed, but the opposite trend was observed in ‘Hort16A’. In conclusion, analysis of the kfALP provides new insights into the potential mechanisms underlying amyloplast B&amp;D with relevance to key fruit quality traits in contrasting kiwifruit cultivars.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Cell polarity is the foundation of cell development and tissue morphogenesis. The investigation of polarized growth provides opportunities to gain profound insights into morphogenesis and tissue functionality in organisms. Currently, there are still many mysteries surrounding the mechanisms that regulate polarized cell growth. Cotton fiber cells serve as an excellent model for studying polarized growth, and provide important clues for unraveling the molecular mechanisms, signaling pathways, and regulatory networks of polarized growth. In this study, we characterized two functional genes, <jats:italic>GhMDHAR1A</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub><jats:italic>/D</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub> and <jats:italic>GhDHAR2A</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub><jats:italic>/D</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub> with predominant expression during fiber elongation. Loss of function of both genes contributed to a significant increase in fiber length. Transcriptomic data revealed up‐regulated expression of antioxidant genes in CRISPR mutant lines, along with delayed expression of secondary wall‐related genes and temporally prolonged expression of primary wall‐related genes. Experimental evidence demonstrated that the increase in GSH content and glutathione peroxidase (GPX) enzyme activity led to enhanced total antioxidant capacity (T‐AOC), resulting in reduced H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> levels, which contributed to the extension of fiber elongation stage in CRISPR mutant lines. Moreover, the increased polysaccharide synthesis in CRISPR mutant lines was found to provide an abundant supply of raw materials for fiber cell wall elongation, suggesting that synergistic interplay between redox homeostasis and polysaccharide synthesis in fiber cells may facilitate cell wall remodeling and fiber elongation. This study provides valuable insights for deciphering the mechanisms of cell polarized growth and improving cotton fiber quality.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Thermosensitive genic female sterility (TGFS) is a promising property to be utilized for hybrid breeding. Here, we identified a rice TGFS line, <jats:italic>tfs2</jats:italic>, through an ethyl methyl sulfone (EMS) mutagenesis strategy. This line showed sterility under high temperature and became fertile under low temperature. Few seeds were produced when the <jats:italic>tfs2</jats:italic> stigma was pollinated, indicating that <jats:italic>tfs2</jats:italic> is female sterile. Gene cloning and genetic complementation showed that a point mutation from leucine to phenylalanine in HEI10 (HEI10<jats:sup><jats:italic>tfs2</jats:italic></jats:sup>), a crossover formation protein, caused the TGFS trait of <jats:italic>tfs2</jats:italic>. Under high temperature, abnormal univalents were formed, and the chromosomes were unequally segregated during meiosis, similar to the reported meiotic defects in <jats:italic>oshei10</jats:italic>. Under low temperature, the number of univalents was largely reduced, and the chromosomes segregated equally, suggesting that crossover formation was restored in <jats:italic>tfs2</jats:italic>. Yeast two‐hybrid assays showed that HEI10 interacted with two putative protein degradation‐related proteins, RPT4 and SRFP1. Through transient expression in tobacco leaves, HEI10 were found to spontaneously aggregate into dot‐like foci in the nucleus under high temperature, but HEI10<jats:sup><jats:italic>tfs2</jats:italic></jats:sup> failed to aggregate. In contrast, low temperature promoted HEI10<jats:sup><jats:italic>tfs2</jats:italic></jats:sup> aggregation. This result suggests that protein aggregation at the crossover position contributes to the fertility restoration of <jats:italic>tfs2</jats:italic> under low temperature. In addition, RPT4 and SRFP1 also aggregated into dot‐like foci, and these aggregations depend on the presence of HEI10. These findings reveal a novel mechanism of fertility restoration and facilitate further understanding of HEI10 in meiotic crossover formation.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Seeds of the root parasitic plant <jats:italic>Striga hermonthica</jats:italic> undergo a conditioning process under humid and warm environments before germinating in response to host‐released stimulants, particularly strigolactones (SLs). The plant hormone abscisic acid (ABA) regulates different growth and developmental processes, and stress response; however, its role during Striga seed germination and early interactions with host plants is under‐investigated. Here, we show that ABA inhibited Striga seed germination and that hindering its biosynthesis induced conditioning and germination in unconditioned seeds, which was significantly enhanced by treatment with the SL analog <jats:italic>rac</jats:italic>‐GR24. However, the inhibitory effect of ABA remarkably decreased during conditioning, confirming the loss of sensitivity towards ABA in later developmental stages. ABA measurement showed a substantial reduction of its content during the early conditioning stage and a significant increase upon <jats:italic>rac</jats:italic>‐GR24‐triggered germination. We observed this increase also in released seed exudates, which was further confirmed by using the Arabidopsis ABA‐reporter GUS marker line. Seed exudates of germinated seeds, containing elevated levels of ABA, impaired the germination of surrounding Striga seeds <jats:italic>in vitro</jats:italic> and promoted root growth of a rice host towards germinated Striga seeds. Application of ABA as a positive control caused similar effects, indicating its function in Striga/Striga and Striga/host communications. In summary, we show that ABA is an essential player during seed dormancy and germination processes in Striga and acts as a rhizospheric signal likely to support host infestation.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Global climate change is predicted to result in increased yield losses of agricultural crops caused by environmental conditions. In particular, heat and drought stress are major factors that negatively affect plant development and reproduction, and previous studies have revealed how these stresses induce plant responses at physiological and molecular levels. Here, we provide a comprehensive overview of current knowledge concerning how drought, heat, and combinations of these stress conditions affect the status of plants, including crops, by affecting factors such as stomatal conductance, photosynthetic activity, cellular oxidative conditions, metabolomic profiles, and molecular signaling mechanisms. We further discuss stress‐responsive regulatory factors such as transcription factors and signaling factors, which play critical roles in adaptation to both drought and heat stress conditions and potentially function as ‘hubs’ in drought and/or heat stress responses. Additionally, we present recent findings based on forward genetic approaches that reveal natural variations in agricultural crops that play critical roles in agricultural traits under drought and/or heat conditions. Finally, we provide an overview of the application of decades of study results to actual agricultural fields as a strategy to increase drought and/or heat stress tolerance. This review summarizes our current understanding of plant responses to drought, heat, and combinations of these stress conditions.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p><jats:italic>Phanera championii</jats:italic> is a medicinal liana plant that has successfully adapted to hostile karst habitats. Despite extensive research on its medicinal components and pharmacological effects, the molecular mechanisms underlying the biosynthesis of critical flavonoids and its adaptation to karst habitats remain elusive. In this study, we performed high‐coverage PacBio and Hi‐C sequencing of <jats:italic>P. championii</jats:italic>, which revealed its high heterozygosity and phased the genome into two haplotypes: Hap1 (384.60 Mb) and Hap2 (383.70 Mb), encompassing a total of 58 612 annotated genes. Comparative genomes analysis revealed that <jats:italic>P. championii</jats:italic> experienced two whole‐genome duplications (WGDs), with approximately 59.59% of genes originating from WGD events, thereby providing a valuable genetic resource for <jats:italic>P. championii</jats:italic>. Moreover, we identified a total of 112 genes that were strongly positively selected. Additionally, about 81.60 Mb of structural variations between the two haplotypes. The allele‐specific expression patterns suggested that the dominant effect of <jats:italic>P. championii</jats:italic> was the elimination of deleterious mutations and the promotion of beneficial mutations to enhance fitness. Moreover, our transcriptome and metabolome analysis revealed alleles in different tissues or different haplotypes collectively regulate the synthesis of flavonoid metabolites. In summary, our comprehensive study highlights the significance of genomic and morphological adaptation in the successful adaptation of <jats:italic>P. championii</jats:italic> to karst habitats. The high‐quality phased genomes obtained in this study serve as invaluable genomic resources for various applications, including germplasm conservation, breeding, evolutionary studies, and elucidation of pathways governing key biological traits of <jats:italic>P. championii</jats:italic>.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Fruit color is one of the most important traits in peppers due to its esthetic value and nutritional benefits and is determined by carotenoid composition, resulting from diverse mutations of carotenoid biosynthetic genes. The EMS204 line, derived from an EMS mutant population, presents bright‐red color, compared with the wild type Yuwolcho cultivar. HPLC analysis indicates that EMS204 fruit contains more zeaxanthin and less capsanthin and capsorubin than Yuwolcho. MutMap was used to reveal the color variation of EMS204 using an F<jats:sub>3</jats:sub> population derived from a cross of EMS204 and Yuwolcho, and the locus was mapped to a 2.5‐Mbp region on chromosome 2. Among the genes in the region, a missense mutation was found in <jats:italic>ZEP</jats:italic> (<jats:italic>zeaxanthin epoxidase</jats:italic>) that results in an amino acid sequence alteration (V291 → I). A color complementation experiment with <jats:italic>Escherichia coli</jats:italic> and ZEP in vitro assay using thylakoid membranes revealed decreased enzymatic activity of EMS204 ZEP. Analysis of endogenous plant hormones revealed a significant reduction in abscisic acid content in EMS204. Germination assays and salinity stress experiments corroborated the lower ABA levels in the seeds. Virus‐induced gene silencing showed that <jats:italic>ZEP</jats:italic> silencing also results in bright‐red fruit containing less capsanthin but more zeaxanthin than control. A germplasm survey of red color accessions revealed no similar carotenoid profiles to EMS204. However, a breeding line containing a <jats:italic>ZEP</jats:italic> mutation showed a very similar carotenoid profile to EMS204. Our results provide a novel breeding strategy to develop red pepper cultivars containing high zeaxanthin contents using <jats:italic>ZEP</jats:italic> mutations.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>In eukaryotes, double‐strand breaks (DSBs) are either repaired by homologous recombination (HR) or non‐homologous end‐joining (NHEJ). In somatic plant cells, HR is very inefficient. Therefore, the vast majority of DSBs are repaired by two different pathways of NHEJ. The classical (cNHEJ) pathway depends on the heterodimer KU70/KU80, while polymerase theta (POLQ) is central to the alternative (aNHEJ) pathway. Surprisingly, Arabidopsis plants are viable, even when both pathways are impaired. However, they exhibit severe growth retardation and reduced fertility. Analysis of mitotic anaphases indicates that the double mutant is characterized by a dramatic increase in chromosome fragmentation due to defective DSB repair. In contrast to the single mutants, the double mutant was found to be highly sensitive to the DSB‐inducing genotoxin bleomycin. Thus, both pathways can complement for each other efficiently in DSB repair. We speculated that in the absence of both NHEJ pathways, HR might be enhanced. This would be especially attractive for gene targeting (GT) in which predefined changes are introduced using a homologous template. Unexpectedly, the <jats:italic>polq</jats:italic> single mutant as well as the double mutant showed significantly lower GT frequencies in comparison to wildtype plants. Accordingly, we were able to show that elimination of both NHEJ pathways does not pose an attractive approach for <jats:italic>Agrobacterium</jats:italic>‐mediated GT. However, our results clearly indicate that a loss of cNHEJ leads to an increase in GT frequency, which is especially drastic and attractive for practical applications, in which the <jats:italic>in planta</jats:italic> GT strategy is used.</jats:p>