Plant Biotechnology Journal最新文献

Fruit size is not only a crucial fitness trait in plant evolution but also an important agronomic target in crop domestication and improvement, yet its regulatory mechanisms remain poorly characterized. Here, we identified an F-box E3 ubiquitin ligase gene, GhEBS1 (ENLARGED BOLL SIZE 1), as a positive regulator of cotton boll size via map-based cloning. An 845-bp structural variant in the promoter-proximal intronic region of GhEBS1 alters local chromatin accessibility and histone modifications, specifically H3K27 and H3K9 methylation levels and acetylation, thereby modulating GhEBS1 expression and driving boll size divergence. Overexpression or heterologous expression of GhEBS1 in cotton (capsule), tomato (berry) and Arabidopsis (silique) promoted fruit enlargement, indicating its functional conservation. Further analysis showed that GhEBS1 interacts with GhPPD1/2 and GhKIX8/9 to modulate downstream cell proliferation-related genes to control cell number and boll size. Breeding evaluations confirm that the elite GhEBS1^L allele significantly increases boll size, seed size and boll weight. Haplotype analysis reveals that GhEBS1^L originated from Gossypium hirsutum race latifolium and underwent artificial selection during cotton domestication. Our findings provide new insights into the regulation of plant fruit size and present a valuable genetic locus for crop yield improvement.

Red light accelerates tomato fruit ripening, but the molecular link between light signalling and autophagy remains unclear. Here, we show that red light promotes fruit coloration by activating autophagy in tomato pericarp. This response largely depends on the transcription factor HY5, which positively regulates this process by directly activating ATG10 expression. ATG10 overexpression rescues the autophagic activity and the delayed coloration of hy5 mutants. Thus, the HY5-ATG10 module links red light to autophagy and fruit maturation, suggesting a target for improving fruit colour.

The plant-derived specialized metabolite montbretin A (MbA) is under development as an improved treatment for Type 2 diabetes, a worldwide epidemic. MbA is an acylated flavonol glycoside so far only found in small amounts in montbretia (Crocosmia × crocosmiiflora) corms. The compound's structural complexity and low natural abundance present major challenges for large-scale production. To enable the development of a scalable MbA production system, we have previously engineered Nicotiana benthamiana to produce MbA. In addition to low levels of MbA, N. benthamiana also produces the pharmaceutically inactive analogues montbretin B and montbretin C, differing from MbA only in their acyl moieties. Follow-up research focusing on precursor engineering has improved MbA yield, but further yield optimization is required to establish N. benthamiana as a scalable MbA production system. Here, we report evidence that transport likely constrains heterologous montbretin production in N. benthamiana and that transporters can be leveraged as bioengineering tools to enhance yield. Specifically, co-expression of tonoplast localized CcABCC4 transporters with montbretin biosynthetic genes in N. benthamiana increased montbretin levels, including those of MbA. Yield increase is likely due to vacuolar sequestration and relies on the presence of an acyl group on the molecule. Eight out of fifteen ABCC4/14 transporters from plant species not known to produce montbretins also enhanced montbretin accumulation in N. benthamiana. These observations suggest that ABCC transporters might be versatile tools for bioengineering.

Jasmonate (JA) regulates defence responses in plants. However, JA-induced defence often results in growth inhibition. This process is largely mediated by MYC2, the master regulator of JA signalling. Nevertheless, the underlying molecular mechanisms have not yet been fully uncovered. Here, we discovered that the ERF transcription factor NaERF_IDOG plays a key role in the JA-induced defence over growth in Nicotiana attenuata upon infection by the notorious fungal pathogen Alternaria alternata. NaERF_IDOG expression was directly controlled by JA through NaMYC2a/b. Plants silenced or knocked out for either NaERF_IDOG or both NaMYC2a and NaMYC2b exhibited similar phenotypes: they were both more vulnerable to A. alternata but grew larger. However, stable overexpression of NaERF_IDOG increased resistance to the fungus and reduced growth in both wild-type (WT) plants and those co-silenced with NaMYC2a/b to a similar extent. Further analysis indicated that NaERF_IDOG binds directly to the promoters of the biosynthetic genes for scopoletin, JA and GA, including NaF6'H1, NaAOS and NaKAO1-like, thereby activating scopoletin and JA biosynthesis while suppressing GA biosynthesis. Finally, our results revealed that both increasing scopoletin levels and reducing GA biosynthesis were involved in JA-induced disease resistance and growth inhibition. Thus, our study revealed how JA prioritizes defence against A. alternata over growth by a novel regulatory network, JA-MYC2-ERF_IDOG-Scopoletin/JA/GA. These findings provide new insights into the molecular mechanisms underlying the trade-off between defence and growth in plants and highlight the key role of NaERF_IDOG in the biosynthesis of scopoletin, JA and GA.

Grain size is a critical agronomic trait, yet the molecular mechanisms governing its determination in crops remain incompletely understood. While recent studies revealed that OsRING80 facilitates DENSE AND ERECT PANICLE 2 (DEP2) degradation to mediate immunity without impacting growth and development, our work identifies a distinct regulatory pathway controlling grain development. We demonstrate that two RING finger E3 ubiquitin ligases, SEVEN IN ABSENTIA 3 (SINA3) and SINA5, post-translationally regulate the stability of DEP2 (also known as SRS1/EP2/OsRELA/SUG1) to modulate grain size. SINA3 and SINA5 physically interact with DEP2, specifically mediated through the C1 structural region of DEP2 containing a coiled-coil domain. These E3 ligases promote K48-linked polyubiquitination of DEP2, targeting it for proteasomal degradation. Liquid chromatography-mass spectrometry (LC–MS) analysis identified six critical lysine residues (K399, K722, K746, K958, K962 and K1344) within DEP2 that are essential for its ubiquitylation and subsequent destabilization. Our genetic evidence further supports this regulatory module: knockout of SINA3 and/or SINA5 leads to DEP2 accumulation, concomitantly increasing grain size and 1000-grain weight significantly, without altering other agronomic traits; conversely, overexpression of SINA3 or SINA5 reduces DEP2 protein levels and diminishes grain size and weight. Therefore, our study uncovers a novel post-translational regulatory module where SINA3 and SINA5 control DEP2 stability to fine-tune grain development. These findings present a promising strategy for optimizing grain yield by manipulating this post-translational regulatory node.