Catálogo de publicaciones - revistas

<jats:title>SUMMARY</jats:title><jats:p>Trichome development is a fascinating model to elaborate the plant cell differentiation and growth processes. A wealth of information has pointed to the contributions of the components associated with cell cycle control and ubiquitin/26S proteasome system (UPS) to trichome morphogenesis, but how these two pathways are connected remains obscure. Here, we report that HECT‐type ubiquitin ligase KAKTUS (KAK) targets the cyclin‐dependent kinase (CDK) inhibitor KRP2 (for kip‐related protein 2) for proteasome‐dependent degradation during trichome branching in Arabidopsis. We show that over‐expression of <jats:italic>KRP2</jats:italic> promotes trichome branching and endoreduplication which is similar to <jats:italic>kak</jats:italic> loss of function mutants. KAK directly interacts with KRP2 and mediates KRP2 degradation. Mutation of <jats:italic>KAK</jats:italic> results in the accumulation of steady‐state KRP2. Consistently, in <jats:italic>kak pKRP2:KRP2‐GFP</jats:italic> plants, the trichome branching is further induced compared with the single mutant. Taken together, our studies bridge the cell cycle control and UPS pathways during trichome development and underscore the importance of post‐translational control in epidermal differentiation.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Bensulfuron‐methyl (BSM) is a widely used herbicide in rice cultivation, but the mechanisms underlying its efficient uptake in rice are poorly understood. In this study, a yeast library expressing 1385 rice transporters was employed to screen proteins sensitive to BSM. As a result, a cyclic nucleotide‐gated channel (CNGC) protein, OsCNGC12, was identified. By inactivating the <jats:italic>OsCNGC12</jats:italic> function via gene editing, we developed BSM‐tolerant rice lines. Our results showed that the <jats:italic>OsCNGC12</jats:italic> mutant rice not only reduced BSM uptake but also promoted Ca<jats:sup>2+</jats:sup> influx in the roots, leading to enhanced non‐target‐site tolerance to BSM. OsCNGC12 is localized in the plasma membrane and is abundantly expressed in the root caps, root vascular bundles, stems, and leaves, indicating its vital role in the distribution of BSM in rice. The indispensability of His‐236, Gln‐240, and Arg‐268 in BSM perception in yeast was demonstrated through targeted mutagenesis of OsCNGC12. Furthermore, we developed a BSM seed coating agent for <jats:italic>OsCNGC12</jats:italic> mutant rice, providing a simplified and cost‐effective means of weed control in direct‐seeded rice. Inclusion, this study showed that disruption of OsCNGC12 confers non‐target‐site tolerance to BSM in rice and has the potential for developing BSM‐resistant rice varieties.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Citrus production is severely threatened by the devastating Huanglongbing (HLB) disease globally. By studying and analyzing the defensive behaviors of an HLB‐tolerant citrus cultivar ‘Shatangju’, we discovered that citrus can sense <jats:italic>Candidatus</jats:italic> Liberibacter asiaticus (<jats:italic>C</jats:italic>Las) infection and induce immune responses against HLB, which can be further strengthened by both endogenously produced and exogenously applied methyl salicylate (MeSA). This immune circuit is turned on by an miR2977‐<jats:italic>SAMT</jats:italic> (encoding a citrus Salicylate [SA] <jats:italic>O</jats:italic>‐methyltransferase) cascade, by which <jats:italic>C</jats:italic>Las infection leads to more in planta MeSA production and aerial emission. We provided both transgenic and multi‐year trail evidences that MeSA is an effective community immune signal. Ambient MeSA accumulation and foliage application can effectively induce defense gene expression and significantly boost citrus performance. We also found that miRNAs are battle fields between citrus and <jats:italic>C</jats:italic>Las, and about 30% of the differential gene expression upon <jats:italic>C</jats:italic>Las infection are regulated by miRNAs. Furthermore, <jats:italic>C</jats:italic>Las hijacks host key processes by manipulating key citrus miRNAs, and citrus employs miRNAs that coordinately regulate defense‐related genes. Based on our results, we proposed that miRNAs and associated components are key targets for engineering or breeding resistant citrus varieties. We anticipate that MeSA‐based management, either induced expression or external application, would be a promising tool for HLB control.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Miraculin‐like proteins (MLPs), members of the Kunitz trypsin inhibitor (KTI) family that are present in various plants, have been discovered to have a role in defending plants against pathogens. In this study, we identified a gene <jats:italic>StMLP1</jats:italic> in potato that belongs to the KTI family. We found that the expression of <jats:italic>StMLP1</jats:italic> gradually increases during <jats:italic>Ralstonia solanacearum</jats:italic> (<jats:italic>R. solanacearum</jats:italic>) infection. We characterized the promoter of <jats:italic>StMLP1</jats:italic> as an inducible promoter that can be triggered by <jats:italic>R. solanacearum</jats:italic> and as a tissue‐specific promoter with specificity for vascular bundle expression. Our findings demonstrate that StMLP1 exhibits trypsin inhibitor activity, and that its signal peptide is essential for proper localization and function. Overexpression of <jats:italic>StMLP1</jats:italic> in potato can enhance the resistance to <jats:italic>R. solanacearum</jats:italic>. Inhibiting the expression of <jats:italic>StMLP1</jats:italic> during infection accelerated the infection by <jats:italic>R. solanacearum</jats:italic> to a certain extent. In addition, the RNA‐seq results of the overexpression‐StMLP1 lines indicated that StMLP1 was involved in potato immunity. All these findings in our study reveal that StMLP1 functions as a positive regulator that is induced and specifically expressed in vascular bundles in response to <jats:italic>R. solanacearum</jats:italic> infection.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p><jats:italic>Schrenkiella parvula</jats:italic>, a leading extremophyte model in Brassicaceae, can grow and complete its lifecycle under multiple environmental stresses, including high salinity. Yet, the key physiological and structural traits underlying its stress‐adapted lifestyle are unknown along with trade‐offs when surviving salt stress at the expense of growth and reproduction. We aimed to identify the influential adaptive trait responses that lead to stress‐resilient and uncompromised growth across developmental stages when treated with salt at levels known to inhibit growth in Arabidopsis and most crops. Its resilient growth was promoted by traits that synergistically allowed primary root growth in seedlings, the expansion of xylem vessels across the root‐shoot continuum, and a high capacity to maintain tissue water levels by developing thicker succulent leaves while enabling photosynthesis during salt stress. A successful transition from vegetative to reproductive phase was initiated by salt‐induced early flowering, resulting in viable seeds. Self‐fertilization in salt‐induced early flowering was dependent upon filament elongation in flowers otherwise aborted in the absence of salt during comparable plant ages. The maintenance of leaf water status promoting growth, and early flowering to ensure reproductive success in a changing environment, were among the most influential traits that contributed to the extremophytic lifestyle of <jats:italic>S. parvula</jats:italic>.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>The genomic integrity of every organism is endangered by various intrinsic and extrinsic stresses. To maintain genomic integrity, a sophisticated DNA damage response (DDR) network is activated rapidly after DNA damage. Notably, the fundamental DDR mechanisms are conserved in eukaryotes. However, knowledge about many regulatory aspects of the plant DDR is still limited. Important, yet little understood, regulatory factors of the DDR are the long non‐coding RNAs (lncRNAs). In humans, 13 lncRNAs functioning in DDR have been characterized to date, whereas no such lncRNAs have been characterized in plants yet. By meta‐analysis, we identified the putative <jats:italic>long intergenic non‐coding RNA induced by DNA damage</jats:italic> (<jats:italic>LINDA</jats:italic>) that responds strongly to various DNA double‐strand break‐inducing treatments, but not to replication stress induced by mitomycin C. After DNA damage, <jats:italic>LINDA</jats:italic> is rapidly induced in an ATM‐ and SOG1‐dependent manner. Intriguingly, the transcriptional response of <jats:italic>LINDA</jats:italic> to DNA damage is similar to that of its flanking hypothetical protein‐encoding gene. Phylogenetic analysis of putative Brassicales and Malvales <jats:italic>LINDA</jats:italic> homologs indicates that <jats:italic>LINDA</jats:italic> lncRNAs originate from duplication of a flanking small protein‐encoding gene followed by pseudogenization. We demonstrate that <jats:italic>LINDA</jats:italic> is not only needed for the regulation of this flanking gene but also fine‐tuning of the DDR after the occurrence of DNA double‐strand breaks. Moreover, <jats:italic>Δlinda</jats:italic> mutant root stem cells are unable to recover from DNA damage, most likely due to hyper‐induced cell death.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Crossovers (COs) are necessary for generating genetic diversity that breeders can select, but there are conserved mechanisms that regulate their frequency and distribution. Increasing CO frequency may raise the efficiency of selection by increasing the chance of integrating more desirable traits. In this study, we characterize rice FANCM and explore its functions in meiotic CO control. <jats:italic>FANCM</jats:italic> mutations do not affect fertility in rice, but they cause a great boost in the overall frequency of COs in both inbred and hybrid rice, according to genetic analysis of the complete set of <jats:italic>fancm zmm</jats:italic> (<jats:italic>hei10</jats:italic>, <jats:italic>ptd</jats:italic>, <jats:italic>shoc1</jats:italic>, <jats:italic>mer3</jats:italic>, <jats:italic>zip4</jats:italic>, <jats:italic>msh4</jats:italic>, <jats:italic>msh5</jats:italic>, and <jats:italic>heip1</jats:italic>) mutants. Although the early homologous recombination events proceed normally in <jats:italic>fancm</jats:italic>, the meiotic extra COs are not marked with HEI10 and require MUS81 resolvase for resolution. FANCM depends on PAIR1, COM1, DMC1, and HUS1 to perform its functions. Simultaneous disruption of <jats:italic>FANCM</jats:italic> and <jats:italic>MEICA1</jats:italic> synergistically increases CO frequency, but it is accompanied by nonhomologous chromosome associations and fragmentations. FANCM interacts with the MHF complex, and ablation of rice <jats:italic>MHF1</jats:italic> or <jats:italic>MHF2</jats:italic> could restore the formation of 12 bivalents in the absence of the ZMM gene <jats:italic>ZIP4</jats:italic>. Our data indicate that unleashing meiotic COs by mutating any member of the FANCM–MHF complex could be an effective procedure to accelerate the efficiency of rice breeding.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Chickpea is among the top three legumes produced and consumed worldwide. Early plant vigor, characterized by good germination and rapid seedling growth, is an important agronomic trait in many crops including chickpea, and shows a positive correlation with seed size. In this study, we report a gamma‐ray‐induced chickpea mutant with a larger organ and seed size. The mutant (<jats:italic>elm</jats:italic>) exhibits increased early vigor and contains higher proline that contributes to a better tolerance under salt stress at germination, seedling, and early vegetative phase. The trait is governed as monogenic recessive, with wild‐type allele being incompletely dominant over the mutant. Genetic mapping of this locus (<jats:italic>CaEl</jats:italic>) identified it as a previously uncharacterized gene (101503252) in chromosome 1 of the chickpea genome. There is a deletion of this gene in the mutant with a complete loss of expression. <jats:italic>In silico</jats:italic> analysis suggests that the gene is present as a single copy in chickpea and related legumes of the galegoid clade. In the mutant, cell division and expansion are affected. Transcriptome profiling identified differentially regulated transcripts related to cell division, expansion, cell wall organization, and metabolism in the mutant. The mutant can be exploited in chickpea breeding programs for increasing plant vigor and seed size.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>The Pacific crabapple (<jats:italic>Malus fusca</jats:italic>) is a wild relative of the commercial apple (<jats:italic>Malus</jats:italic> × <jats:italic>domestica</jats:italic>). With a range extending from Alaska to Northern California, <jats:italic>M. fusca</jats:italic> is extremely hardy and disease resistant. The species represents an untapped genetic resource for the development of new apple cultivars with enhanced stress resistance. However, gene discovery and utilization of <jats:italic>M. fusca</jats:italic> have been hampered by the lack of genomic resources. Here, we present a high‐quality, haplotype‐resolved, chromosome‐scale genome assembly and annotation for <jats:italic>M. fusca</jats:italic>. The genome was assembled using high‐fidelity long‐reads and scaffolded using genetic maps and high‐throughput chromatin conformation capture sequencing, resulting in one of the most contiguous apple genomes to date. We annotated the genome using public transcriptomic data from the same species taken from diverse plant structures and developmental stages. Using this assembly, we explored haplotypic structural variation within the genome of <jats:italic>M. fusca</jats:italic>, identifying thousands of large variants. We further showed high sequence co‐linearity with other domesticated and wild <jats:italic>Malus</jats:italic> species. Finally, we resolve a known quantitative trait locus associated with resistance to fire blight (<jats:italic>Erwinia amylovora</jats:italic>). Insights gained from the assembly of a reference‐quality genome of this hardy wild apple relative will be invaluable as a tool to facilitate DNA‐informed introgression breeding.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Inorganic phosphate (Pi) homeostasis is essential for plant growth and depends on the transport of Pi across cells. In <jats:italic>Arabidopsis thaliana</jats:italic>, PHOSPHATE 1 (PHO1) is present in the root pericycle and xylem parenchyma where it exports Pi into the xylem apoplast for its transfer to shoots. PHO1 consists of a cytosolic SPX domain followed by membrane‐spanning α‐helices and ends with the EXS domain, which participates in the steady‐state localization of PHO1 to the Golgi and <jats:italic>trans</jats:italic>‐Golgi network (TGN). However, PHO1 exports Pi across the plasma membrane (PM), making its localization difficult to reconcile with its function. To investigate whether PHO1 transiently associates with the PM, we inhibited clathrin‐mediated endocytosis (CME) by overexpressing <jats:italic>AUXILIN‐LIKE 2</jats:italic> or <jats:italic>HUB1</jats:italic>. Inhibiting CME resulted in PHO1 re‐localization from the Golgi/TGN to the PM when <jats:italic>PHO1</jats:italic> was expressed in Arabidopsis root pericycle or epidermis or <jats:italic>Nicotiana benthamiana</jats:italic> leaf epidermal cells. A fusion protein between the PHO1 EXS region and GFP was stabilized at the PM by CME inhibition, indicating that the EXS domain plays an important role in sorting PHO1 to/from the PM. PHO1 internalization from the PM occurred independently of AP2 and was not influenced by Pi deficiency, the ubiquitin‐conjugating E2 PHO2, or the potential ubiquitination of cytosolic lysines in the EXS domain. PM‐stabilized PHO1 showed reduced root‐to‐shoot Pi export activity, indicating that CME of PHO1 may be important for its optimal Pi export activity and plant Pi homeostasis.</jats:p>