A pathogen may cause infected plants to promote the performance of its transmitting vector, which accelerates the spread of the pathogen. This positive effect of a pathogen on its vector via their shared host plant is termed indirect mutualism. For example, terpene biosynthesis is suppressed in begomovirus-infected plants, leading to reduced plant resistance and enhanced performance of the whiteflies (Bemisia tabaci) that transmit these viruses. Although begomovirus-whitefly mutualism has been known, the underlying mechanism is still elusive. Here, we identified bC1 of Tomato yellow leaf curl China virus, a monopartite begomovirus, as the viral genetic factor that suppresses plant terpene biosynthesis. bC1 directly interacts with the basic helix-loop-helix transcription factor MYC2 to compromise the activation of MYC2-regulated terpene synthase genes, thereby reducing whitefly resistance. MYC2 associates with the bipartite begomoviral protein BV1, suggesting that MYC2 is an evolutionarily conserved target of begomoviruses for the suppression of terpene-based resistance and the promotion of vector performance. Our findings describe how this viral pathogen regulates host plant metabolism to establish mutualism with its insect vector.

Most of the world's natural fiber comes from cotton (Gossypium spp.), which is an important crop worldwide. Characterizing genes that regulate cotton yield and fiber quality is expected to benefit the sustainable production of natural fiber. Although a huge number of expressed sequence tag sequences are now available in the public database, large-scale gene function analysis has been hampered by the low-efficiency process of generating transgenic cotton plants. Tobacco rattle virus (TRV) has recently been reported to trigger virus-induced gene silencing (VIGS) in cotton leaves. Here, we extended the utility of this method by showing that TRV-VIGS can operate in reproductive organs as well. We used this method to investigate the function of KATANIN and WRINKLED1 in cotton plant development. Cotton plants with suppressed KATANIN expression produced shorter fibers and elevated weight ratio of seed oil to endosperm. By contrast, silencing of WRINKLED1 expression resulted in increased fiber length but reduced oil seed content, suggesting the possibility to increase fiber length by repartitioning carbon flow. Our results provide evidence that the TRV-VIGS system can be used for rapid functional analysis of genes involved in cotton fiber development.

Fundamental photocatalyticl imitations of solar CO 2 reduction remaind ue to low efficiency,s eriousc harge recombination, and short lifetime of catalysts. Herein, twodimensional graphitic carbon nitride nanosheets with nitrogen vacancies (g-C 3 N x )l ocateda tboth three-coordinateN atoms and uncondensed terminal NH x species were prepared by one-step tartaric acid-assistantt hermal polymerization of dicyandiamide. Transient absorption spectra revealed that the defects in g-C 3 N 4 act as trapped states of chargest or esult in prolonged lifetimes of photoexcited charge carriers. Time-resolved photoluminescence spectroscopy revealed that the faster decay of chargesi sd ue to the decreased interlayer stacking distance in g-C 3 N x in favor of hopping transition and mobility of charge carriers to the surface of the material. Owing to the synergic virtues of strong visible-light absorption, large surface area, and efficient charges eparation, the g-C 3 N x nanosheets with negligible loss after 15 ho fp hotocatalysis exhibited aC Oe volution rate of 56.9 mmol g À1 h À1 under visible-light irradiation, which is roughlye ight times higher than that of pristine g-C 3 N 4 . This work presentst he role of defects in modulating light absorption and charge separation, which opens an avenue to robust solar-energyc onversion performance.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

BackgroundJatropha curcas is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty acids profile of the oil has a direct impact on ignition quality, heat of combustion and oxidative stability. An ideal biodiesel composition should have more monounsaturated fatty acids and less polyunsaturated acids. Jatropha seed oil contains 30% to 50% polyunsaturated fatty acids (mainly linoleic acid) which negatively impacts the oxidative stability and causes high rate of nitrogen oxides emission.ResultsThe enzyme 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. We identified three putative delta 12 fatty acid desaturase genes in Jatropha (JcFAD2s) through genome-wide analysis and downregulated the expression of one of these genes, JcFAD2-1, in a seed-specific manner by RNA interference technology. The resulting JcFAD2-1 RNA interference transgenic plants showed a dramatic increase of oleic acid (> 78%) and a corresponding reduction in polyunsaturated fatty acids (< 3%) in its seed oil. The control Jatropha had around 37% oleic acid and 41% polyunsaturated fatty acids. This indicates that FAD2-1 is the major enzyme responsible for converting oleic acid to linoleic acid in Jatropha. Due to the changes in the fatty acids profile, the oil of the JcFAD2-1 RNA interference seed was estimated to yield a cetane number as high as 60.2, which is similar to the required cetane number for conventional premium diesel fuels (60) in Europe. The presence of high seed oleic acid did not have a negative impact on other Jatropha agronomic traits based on our preliminary data of the original plants under greenhouse conditions. Further, we developed a marker-free system to generate the transgenic Jatropha that will help reduce public concerns for environmental issues surrounding genetically modified plants.ConclusionIn this study we produced seed-specific JcFAD2-1 RNA interference transgenic Jatropha without a selectable marker. We successfully increased the proportion of oleic acid versus linoleic in Jatropha through genetic engineering, enhancing the quality of its oil.

Preferred‐orientation control has significant impact on the separation performance of MOF membranes. Under most conditions the preferred orientation of MOF membranes is dominated by the Van der Drift mechanism of evolutionary growth selection so that the obtained orientation may not be optimized for practical application. In this study, highly c‐oriented NH2‐MIL‐125 membranes were prepared on porous α‐alumina substrates by combining oriented seeding and controlled in‐plane epitaxial growth. Dynamic air–liquid interface‐assisted self‐assembly of c‐oriented NH2‐MIL‐125(Ti) seed monolayers, the use of layered TiS2 as the metal precursor, and single‐mode microwave heating were crucial in ensuring the preferred c‐orientation while simultaneously suppressing undesired twin growth. Owing to reduced grain boundary defects, the prepared c‐oriented membranes showed an ideal H2/CO2 selectivity of 24.8, which was 6.1 times higher than that of their randomly oriented counterparts under similar operating conditions.

Conversion of CO2 to sustainable chemical feedstocks and fuels by reacting with renewable hydrogen is considered to be a promising direction in energy research. The selectivity of desired products, such as C2–C4 = and C5+, is low over unpromoted iron-based catalysts for CO2 hydrogenation. Therefore, promoters are often used to tailor and optimize the product distribution. In this work, the effect of doping Cu into Fe-based supported catalysts on the catalytic performance for CO2 hydrogenation to hydrocarbons was studied with a particularly focus on the interaction between Fe and Cu. For this purpose, catalysts with different Fe and Cu distribution were prepared by various impregnation methods. It was found that the selectivity of C2–C4 = over Cu-promoted catalysts decreased, but a significant improvement was obtained for C5+. This promoting behavior is different from that of other promoters (e.g., K, Mn, Zn, etc.). The secondary conversion of produced olefins on Cu-promoted catalysts, which results from the improvement of olefins adsorption, on Cu-promoted catalysts leads to the decrease of C2–C4 = (hydrogenation) but the increase of C5+ (oligomerization). Characterization results demonstrate that the catalytic performance is evidently associated with the strength of the interaction between Fe and Cu in the supported catalysts.

No abstract

Aberrant viral RNAs produced in infected plant cells serve as templates for the synthesis of dsRNAs. The derived virus-related small interfering RNAs (siRNA) mediate cleavage of viral RNAs by post-transcriptional gene silencing (PTGS), thus blocking virus multiplication. Here, we identified ASYMMETRIC LEAVES2 (AS2) as a new component of plant P body complex which mediates mRNA decapping and degradation. We found that AS2 promotes DCP2 decapping activity, accelerates mRNA turnover rate, inhibits siRNA accumulation and functions as an endogenous suppressor of PTGS. Consistent with these findings, as2 mutant plants are resistant to virus infection whereas AS2 over-expression plants are hypersensitive. The geminivirus nuclear shuttle protein BV1 protein, which shuttles between nuclei and cytoplasm, induces AS2 expression, causes nuclear exit of AS2 to activate DCP2 decapping activity and renders infected plants more sensitive to viruses. These principles of gene induction and shuttling of induced proteins to promote mRNA decapping in the cytosol may be used by viral pathogens to weaken antiviral defenses in host plants.