Catálogo de publicaciones - revistas

<jats:title>SUMMARY</jats:title><jats:p>Understanding the underlying mechanisms of plant development is crucial to successfully steer or manipulate plant growth in a targeted manner. Leaves, the primary sites of photosynthesis, are vital organs for many plant species, and leaf growth is controlled by a tight temporal and spatial regulatory network. In this review, we focus on the genetic networks governing leaf cell proliferation, one major contributor to final leaf size. First, we provide an overview of six regulator families of leaf growth in Arabidopsis: DA1, PEAPODs, KLU, GRFs, the SWI/SNF complexes, and DELLAs, together with their surrounding genetic networks. Next, we discuss their evolutionary conservation to highlight similarities and differences among species, because knowledge transfer between species remains a big challenge. Finally, we focus on the increase in knowledge of the interconnectedness between these genetic pathways, the function of the cell cycle machinery as their central convergence point, and other internal and environmental cues.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Plant NAC transcription factors play a crucial role in enhancing cold stress tolerance, yet the precise molecular mechanisms underlying cold stress remain elusive. In this study, we identified and characterized <jats:italic>CaNAC035</jats:italic>, an NAC transcription factor isolated from pepper (<jats:italic>Capsicum annuum</jats:italic>) leaves. We observed that the expression of the <jats:italic>CaNAC035</jats:italic> gene is induced by both cold and abscisic acid (ABA) treatments, and we elucidated its positive regulatory role in cold stress tolerance. Overexpression of <jats:italic>CaNAC035</jats:italic> resulted in enhanced cold stress tolerance, while knockdown of <jats:italic>CaNAC035</jats:italic> significantly reduced resistance to cold stress. Additionally, we discovered that CaSnRK2.4, a SnRK2 protein, plays an essential role in cold tolerance. In this study, we demonstrated that CaSnRK2.4 physically interacts with and phosphorylates CaNAC035 both <jats:italic>in vitro</jats:italic> and <jats:italic>in vivo</jats:italic>. Moreover, the expression of two ABA biosynthesis‐related genes, <jats:italic>CaAAO3</jats:italic> and <jats:italic>CaNCED3</jats:italic>, was significantly upregulated in the <jats:italic>CaNAC035</jats:italic>‐overexpressing transgenic pepper lines. Yeast one‐hybrid, Dual Luciferase, and electrophoretic mobility shift assays provided evidence that CaNAC035 binds to the promoter regions of both <jats:italic>CaAAO3</jats:italic> and <jats:italic>CaNCED3 in vivo</jats:italic> and <jats:italic>in vitro</jats:italic>. Notably, treatment of transgenic pepper with 50 μ<jats:sc>m</jats:sc> Fluridone (Flu) enhanced cold tolerance, while the exogenous application of ABA at a concentration of 10 μ<jats:sc>m</jats:sc> noticeably reduced cold tolerance in the virus‐induced gene silencing line. Overall, our findings highlight the involvement of <jats:italic>CaNAC035</jats:italic> in the cold response of pepper and provide valuable insights into the molecular mechanisms underlying cold tolerance. These results offer promising prospects for molecular breeding strategies aimed at improving cold tolerance in pepper and other crops.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>The Cys2/His2 (C2H2)‐type zinc finger family has been reported to regulate multiple aspects of plant development and abiotic stress response. However, the role of C2H2‐type zinc finger proteins in cold tolerance remains largely unclear. Through RNA‐sequence analysis, a cold‐responsive zinc finger protein, named as <jats:italic>PtrZAT12</jats:italic>, was identified and isolated from trifoliate orange (<jats:italic>Poncirus trifoliata</jats:italic> L. Raf.), a cold‐hardy plant closely related to citrus. Furthermore, we found that <jats:italic>PtrZAT12</jats:italic> was markedly induced by various abiotic stresses, especially cold stress. PtrZAT12 is a nuclear protein, and physiological analysis suggests that overexpression of <jats:italic>PtrZAT12</jats:italic> conferred enhanced cold tolerance in transgenic tobacco (<jats:italic>Nicotiana tabacum</jats:italic>) plants, while knockdown of <jats:italic>PtrZAT12</jats:italic> by virus‐induced gene silencing (VIGS) increased the cold sensitivity of trifoliate orange and repressed expression of genes involved in stress tolerance. The promoter of <jats:italic>PtrZAT12</jats:italic> harbors a DRE/CRT <jats:italic>cis</jats:italic>‐acting element, which was verified to be specifically bound by PtrCBF1 (<jats:italic>Poncirus trifoliata</jats:italic> C‐repeat BINDING FACTOR1). VIGS‐mediated silencing of <jats:italic>PtrCBF1</jats:italic> reduced the relative expression levels of <jats:italic>PtrZAT12</jats:italic> and decreased the cold resistance of trifoliate orange. Based on these results, we propose that <jats:italic>PtrZAT12</jats:italic> is a direct target of CBF1 and plays a positive role in modulation of cold stress tolerance. The knowledge gains new insight into a regulatory module composed of CBF1‐<jats:italic>ZAT12</jats:italic> in response to cold stress and advances our understanding of cold stress response in plants.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Soybean oil is the second most produced edible vegetable oil and is used for many edible and industrial materials. Unfortunately, it has the disadvantage of ‘reversion flavor’ under photooxidative conditions, which produces an off‐odor and decreases the quality of edible oil. Reversion flavor and off‐odor are caused by minor fatty acids in the triacylglycerol of soybean oil known as furan fatty acids, which produce 3‐methyl‐2,4‐nonanedione (3‐MND) upon photooxidation. As a solution to this problem, a reduction in furan fatty acids leads to a decrease in 3‐MND, resulting in a reduction in the off‐odor induced by light exposure. However, there are no reports on the genes related to the biosynthesis of furan fatty acids in soybean oil. In this study, four mutant lines showing low or no furan fatty acid levels in soybean seeds were isolated from a soybean mutant library. Positional cloning experiments and homology search analysis identified two genes responsible for furan fatty acid biosynthesis in soybean: <jats:italic>Glyma.20G201400</jats:italic> and <jats:italic>Glyma.04G054100</jats:italic>. Ectopic expression of both genes produced furan fatty acids in transgenic soybean hairy roots. The structure of these genes is different from that of the furan fatty acid biosynthetic genes in photosynthetic bacteria. Homologs of these two group of genes are widely conserved in the plant kingdom. The purified oil from the furan fatty acid mutant lines had lower amounts of 3‐MND and reduced off‐odor after light exposure, compared with oil from the wild‐type.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Mutant populations are crucial for functional genomics and discovering novel traits for crop breeding. <jats:italic>Sorghum</jats:italic>, a drought and heat‐tolerant C4 species, requires a vast, large‐scale, annotated, and sequenced mutant resource to enhance crop improvement through functional genomics research. Here, we report a sorghum large‐scale sequenced mutant population with 9.5 million ethyl methane sulfonate (EMS)‐induced mutations that covered 98% of sorghum's annotated genes using inbred line BTx623. Remarkably, a total of 610 320 mutations within the promoter and enhancer regions of 18 000 and 11 790 genes, respectively, can be leveraged for novel research of <jats:italic>cis</jats:italic>‐regulatory elements. A comparison of the distribution of mutations in the large‐scale mutant library and sorghum association panel (SAP) provides insights into the influence of selection. EMS‐induced mutations appeared to be random across different regions of the genome without significant enrichment in different sections of a gene, including the 5′ UTR, gene body, and 3′‐UTR. In contrast, there were low variation density in the coding and UTR regions in the SAP. Based on the <jats:italic>K</jats:italic><jats:sub>a</jats:sub>/<jats:italic>K</jats:italic><jats:sub>s</jats:sub> value, the mutant library (~1) experienced little selection, unlike the SAP (0.40), which has been strongly selected through breeding. All mutation data are publicly searchable through SorbMutDB (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.depts.ttu.edu/igcast/sorbmutdb.php">https://www.depts.ttu.edu/igcast/sorbmutdb.php</jats:ext-link>) and SorghumBase (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://sorghumbase.org/">https://sorghumbase.org/</jats:ext-link>). This current large‐scale sequence‐indexed sorghum mutant population is a crucial resource that enriched the sorghum gene pool with novel diversity and a highly valuable tool for the Poaceae family, that will advance plant biology research and crop breeding.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Crocins are glucosylated apocarotenoids present in flowers and fruits of a few plant species, including saffron, gardenia, and <jats:italic>Buddleja</jats:italic>. The biosynthesis of crocins in these plants has been unraveled, and the enzymes engineered for the production of crocins in heterologous systems. Mullein (<jats:italic>Verbascum</jats:italic> sp.) has been identified as a new source of crocins and picrocrocin. In this work, we have identified eight enzymes involved in the cleavage of carotenoids in two <jats:italic>Verbascum</jats:italic> species, <jats:italic>V. giganteum</jats:italic> and <jats:italic>V. sinuatum</jats:italic>. Four of them were homologous to the previously identified BdCCD4.1 and BdCCD4.3 from <jats:italic>Buddleja</jats:italic>, involved in the biosynthesis of crocins. These enzymes were analyzed for apocarotenogenic activity in bacteria and <jats:italic>Nicotiana benthamiana</jats:italic> plants using a virus‐driven system. Metabolic analyses of bacterial extracts and <jats:italic>N. benthamiana</jats:italic> leaves showed the efficient activity of these enzymes to produce crocins using β‐carotene and zeaxanthin as substrates. Accumulations of 0.17% of crocins in <jats:italic>N. benthamiana</jats:italic> dry leaves were reached in only 2 weeks using a recombinant virus expressing VgCCD4.1, similar to the amounts previously produced using the canonical saffron CsCCD2L. The identification of these enzymes, which display a particularly broad substrate spectrum, opens new avenues for apocarotenoid biotechnological production.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Many plants can terminate their flowering process in response to unfavourable environments, but the mechanisms underlying this response are poorly understood. In this study, we observed that the lotus flower buds were susceptible to abortion under shaded conditions. The primary cause of abortion was excessive autophagic cell death (ACD) in flower buds. Blockade of autophagic flux in lotus flower buds consistently resulted in low levels of ACD and improved flowering ability under shaded conditions. Further evidence highlights the importance of the NnSnRK1‐NnATG1 signalling axis in inducing ACD in lotus flower buds and culminating in their timely abortion. Under shaded conditions, elevated levels of NnSnRK1 activated NnATG1, which subsequently led to the formation of numerous autophagosome structures in lotus flower bud cells. Excessive autophagy levels led to the bulk degradation of cellular material, which triggered ACD and the abortion of flower buds. <jats:italic>NnSnRK1</jats:italic> does not act directly on <jats:italic>NnATG1</jats:italic>. Other components, including <jats:italic>TOR</jats:italic> (<jats:italic>target of rapamycin</jats:italic>), <jats:italic>PI3K</jats:italic> (<jats:italic>phosphatidylinositol 3‐kinase</jats:italic>) and three previously unidentified genes, appeared to be pivotal for the interaction between <jats:italic>NnSnRK1</jats:italic> and <jats:italic>NnATG1</jats:italic>. This study reveals the role of autophagy in regulating the abortion of lotus flower buds, which could improve reproductive success and act as an energy‐efficient measure in plants.</jats:p>

<jats:title>SUMMARY</jats:title><jats:p>Abscisic acid (ABA) is involved in salt and drought stress responses, but the underlying molecular mechanism remains unclear. Here, we demonstrated that the overexpression of <jats:italic>MdMYB44‐like</jats:italic>, an R2R3‐MYB transcription factor, significantly increases the salt and drought tolerance of transgenic apples and Arabidopsis. MdMYB44‐like inhibits the transcription of <jats:italic>MdPP2CA</jats:italic>, which encodes a type 2C protein phosphatase that acts as a negative regulator in the ABA response, thereby enhancing ABA signaling‐mediated salt and drought tolerance. Furthermore, we found that MdMYB44‐like and MdPYL8, an ABA receptor, form a protein complex that further enhances the transcriptional inhibition of the <jats:italic>MdPP2CA</jats:italic> promoter by MdMYB44‐like. Significantly, we discovered that MdPP2CA can interfere with the physical association between MdMYB44‐like and MdPYL8 in the presence of ABA, partially blocking the inhibitory effect of the MdMYB44‐like–MdPYL8 complex on the <jats:italic>MdPP2CA</jats:italic> promoter. Thus, MdMYB44‐like, MdPYL8, and MdPP2CA form a regulatory loop that tightly modulates ABA signaling homeostasis under salt and drought stress. Our data reveal that MdMYB44‐like precisely modulates ABA‐mediated salt and drought tolerance in apples through the MdPYL8–MdPP2CA module.</jats:p>