Compared with sole nitrate (NO₃^–) or sole ammonium (NH₄⁺) supply, mixed nitrogen (N) supply may promote growth of maize seedlings.  Previous study suggested that mixed N supply not only increased photosynthesis rate, but also enhanced leaf growth by increasing auxin synthesis to build a large sink for C and N utilization.  However, whether this process depends on N absorption is unknown.  Here, maize seedlings were grown hydroponically with three N forms (NO₃^– only, 75/25 NO₃^–/NH₄⁺ and NH₄⁺ only).  The study results suggested that maize growth rate and N content of shoots under mixed N supply was little different to that under sole NO₃^– supply at 0–3 d, but was higher than under sole NO₃^– supply at 6–9 d.  ¹⁵N influx rate under mixed N supply was greater than under sole NO₃^– or NH₄⁺ supply at 6–9 d, although NO₃^– and NH₄⁺ influx under mixed N supply were reduced compared to sole NO₃^– and NH₄⁺ supply, respectively.  qRT-PCR determination suggested that the increased N absorption under mixed N supply may be related to the higher expression of NO₃^– transporters in roots, such as ZmNRT1.1A, ZmNRT1.1B, ZmNRT1.1C, ZmNRT1.2 and ZmNRT1.3, or NH₄⁺ absorption transporters, such as ZmAMT1.1A, especially the latter.  Furthermore, plants had higher nitrate reductase (NR) glutamine synthase (GS) activity and amino acid content under mixed N supply than when under sole NO₃^– supply.  The experiments with inhibitors of NR reductase and GS synthase further confirmed that N assimilation ability under mixed N supply was necessary to promote maize growth, especially for the reduction of NO₃^– by NR reductase.  This research suggested that the increased processes of NO₃^– and NH₄⁺ assimilation by improving N-absorption ability of roots under mixed N supply may be the main driving force to increase maize growth.

Inversion tillage with straw amendment is widely applied in northeastern China, and it can substantially increase the storage of carbon and improve multiple subsoil functions. Soil microorganisms are believed to be the key to this process, but research into their role in subsoil amelioration is limited. Therefore, a field experiment was conducted in 2018 in a region in northeastern China with Hapli-Udic Cambisol using four treatments: conventional tillage (CT, tillage to a depth of 15 cm with no straw incorporation), straw incorporation with conventional tillage (SCT, tillage to a depth of 15 cm), inversion tillage (IT, tillage to a depth of 35 cm) and straw incorporation with inversion tillage (SIT, tillage to a depth of 35 cm). The soils were managed by inversion to a depth of 15 or 35 cm every year after harvest. The results indicated that SIT improved soil multi-nutrient cycling variables and increased the availability of key nutrients such as soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium in both the topsoil and subsoil. In contrast to CT and SCT, SIT created a looser microbial network structure but with highly centralized clusters by reducing the topological properties of average connectivity and node number, and by increasing the average path length and the modularity. A Random Forest analysis found that the average path length and the clustering coefficient were the main determinants of soil multi-nutrient cycling. These findings suggested that SIT can be an effective option for improving soil multi-nutrient cycling and the structure of microbial networks, and they provide crucial information about the microbial strategies that drive the decomposition of straw in Hapli-Udic Cambisol.

Oomycete, particularly Phytophthora species, causes the most devastating crop diseases, such as potato late blight, and threatens the sustainable crop production worldwide.  Our previous studies identified Resistance to Phytophthora parasitica 1 (RTP1) as a negative regulator of Arabidopsis resistance to multiple biotrophic pathogens and RTP1 loss-of-function plants displayed rapid cell death and reactive oxygen species (ROS) production during early colonization of P. parasitica.  In this study, we aim to decipher the mechanism of RTP1-mediated cell death, and identify a member of vaculoar processing enzymes (VPEs), γVPE, playing a role in rtp1-mediated resistance to P. parasitica and cell death occurrence.  Our results showed up-regulation of the expression of γVPE as well as increased VPE/caspase 1-like protease activity in P. parasitica-infected rtp1 mutant plants.  Besides, we found that the VPE/caspase 1-like protease activity was required for the cell death occurrence in Arabidopsis plants during the infection of P. parasitica as well as rtp1-mediated resistance to P. parasitica.  Further pathogenicity assays on either Arabidopsis γvpe mutant plants or leaves of Nicotiana benthamiana with transient overexpression of γVPE demonstrated γVPE could positively affect plant resistance to P. parasitica.  Together, our studies suggest that γVPE might function as an important regulator of plant defense and cell death occurrence in response to P. parasitica infection, and VPE/caspase 1-like protease activity is required for rtp1-mediated resistance to P. parasitica.

Retrotransposons, a type of DNA fragment that can mobilize itself on genome, can generate genetic variations and develop for molecular markers based on the insertion polymorphism.  Zinc finger proteins (ZNFs) are among the most abundant proteins in eukaryotic animals, and their functions are extraordinarily diverse and particularly important in gene regulation.  In the current study, bioinformatic prediction was performed to screen for retrotransposon insertion polymorphisms (RIPs) in six ZNF genes (ZNF2, ZNF3, ZNF7, ZNF8, ZNF10 and ZNF12).  Six RIPs in these ZNFs, including one short interspersed nuclear element (SINE) RIP in intron 1 and one long interspersed nuclear element 1 (L1) RIP in intron 3 of ZNF2, one SINE RIP in 5´ flanking region and one SINE RIP in intron 2 of ZNF3, one SINE RIP in 3´ UTR of ZNF7 and one L1 RIP in intron 2 of ZNF12, were discovered and their presence was confirmed by PCR.  The impact of the SINE RIP in the first intron of ZNF2, which is close to the core promoter of ZNF2, on the gene activity was investigated by dual-luciferase assay in three cell lines.  Our results showed that the SINE insertion in the intron 1 of ZNF2 repressed the core promoter activity extremely significantly (P<0.01) in cervical cancer cells and porcine primary embryonic fibroblasts (HeLa and PEF), thus SINE may act as a repressor.  This SINE RIP also significantly (P<0.05) affected the corrected back fat thickness in Yorkshire pigs.  The corrected back fat thickness of individuals with SINE insertion in the first intron of ZNF2 was significantly (P<0.05) higher than that of individuals without SINE insertion.  In summary, our data suggested that RIPs play important roles in the genetic variations of these ZNF genes and SINE RIP in the intron 1 of ZNF2 may provide a useful molecular marker for the screening of fat deposition in the pig breeding.

Soybean yield has been increased through high planting density, but investigating plant height and petiole traits to select for compact architecture, lodging resistance, and high yield varieties is an underexplored avenue to improve yield.  We compared the relationship between yield-related traits, lodging resistance, and petiole-associated phenotypes in the short petiole germplasm M657 with three control accessions over 2017-2018 in four locations of the Huang-Huai region.  The results showed M657 exhibited stable and high tolerance to high planting density and resistance to lodging, especially at the highest density (8×10⁵ plants ha^-1).  Regression analysis showed that shorter petiole length was significantly associated with increased lodging resistance.  Yield analysis showed that M657 achieved higher yields under higher densities, especially in the north Huang-Huai region.  There are markedly different responses to intra- and inter-row spacing designs among varieties in both lodging and yield related to location and density.  Lodging was positively correlated with planting density, plant height, petiole length, and number of effective branches, and negatively correlated with stem diameter, seed number per plant, and seed weight per plant.  The yield of soybean was increased by appropriately increasing planting density on the basis of current soybean varieties in the Huang-Huai region.  This study provides a valuable new germplasm resource for introgression of compact architecture traits amenable to high yield in high density planting systems and establishes a high-yield model of soybean in the Huang-Huai region.

Under appropriate culture conditions, plant cells can regenerate new organs or even whole plants.  De novo organ regeneration is an excellent biological system, which usually requires additional growth regulators, including auxin and cytokinin.  Nitrate is an essential nutrient element for plant vegetative and reproductive development.  It has been reported that nitrate is involved in auxin biosynthesis and transport throughout the growth and development of plants.  In this study, we demonstrated that the ectopic expression of the MdNLP7 transcription factor in Arabidopsis could regulate the regeneration of root explants.  MdNLP7 mainly participated in the regulation of callus formation, starting with pericycle cell division, and mainly affected auxin distribution and accumulation in the regulation process.  Moreover, MdNLP7 upregulated the expression of genes related to auxin biosynthesis and transport in the callus formation stage.  The results demonstrated that MdNLP7 may play a role in the nitrate-modulated regeneration of root explants.  Moreover, the results revealed that nitrate–auxin crosstalk is required for de novo callus initiation and clarified the mechanisms of organogenesis.

Plant height is a key plant architectural trait that affects the seed yield, harvest index and lodging resistance in Brassica napus L., although the genetic mechanisms affecting plant height remain unclear.  Here, a semi-dwarf mutant, df34, was obtained by ethyl methanesulphonate-induced mutagenesis.  Genetic analysis showed that the semi-dwarf phenotype is controlled by one semi-dominant gene, which was located on chromosome C03 using a bulked segregant analysis coupled with whole-genome sequencing, and this gene was named BnaSD.C3.  Then BnaSD.C3 was fine-mapped to a 297.35-kb segment of the “Darmor-bzh” genome, but there was no potential candidate gene for the semi-dwarf trait underlying this interval.  Furthermore, the interval was aligned to the Zhongshuang 11 reference genome.  Finally, combining structural variation analysis, transcriptome sequencing, phytohormone analyses and gene annotation information, BnaC03G0466900ZS and BnaC03G0478900ZS were determined to be the most likely candidate genes affecting the plant height of df34.  This study provides a novel major locus for breeding and new insights into the genetic architecture of plant height in B. napus

The MADS-box (DAM) gene PpDAM6, which is related to dormancy, plays a key role in bud endodormancy release, and the expression of PpDAM6 decreases during endodormancy release.  However, the interaction network that governs its regulation of the endodormancy release of flower buds in peach remains unclear.  In this study, we used yeast two-hybrid (Y2H) assays to identify a mitogen-activated protein kinase, PpMAPK6, that interacts with PpDAM6 in a peach dormancy-associated SSHcDNA library.  PpMAPK6 is primarily located in the nucleus, and Y2H and bimolecular fluorescence complementation (BiFC) assays verified that PpMAPK6 interacts with PpDAM6 by binding to the MADS-box domain of PpDAM6.  Quantitative real-time PCR (qRT-PCR) analysis showed that the expression of PpMAPK6 was opposite that of PpDAM6 in the endodormancy release of three cultivars with different chilling requirements (Prunus persica ‘Chunjie’, Prunus persica var. nectarina ‘Zhongyou 5’, Prunus persica ‘Qingzhou peach’).  In addition, abscisic acid (ABA) inhibited the expression of PpMAPK6 and promoted the expression of PpDAM6 in flower buds.  The results indicated that PpMAPK6 might phosphorylate PpDAM6 to accelerate its degradation by interacting with PpDAM6.  The expression of PpMAPK6 increased with decreasing ABA content during endodormancy release in peach flower buds, which in turn decreased the expression of PpDAM6 and promoted endodormancy release.

Starch is the most important component in endosperm, and its synthesis is regulated by multiple transcription factors (TFs) in cereals. However, whether the functions of these TFs are conserved or not among cereals unclear yet. Here, we cloned a B3 family TF, named as TaABI19 based on its orthologous in maize (Zea mays L.). Alignment of DNA and protein showed that ABI19 was conserved in maize and wheat (Triticum aestivum L.). We found that TaABI19 was highly expressed in young spike and developing grains and encoded a nucleus-localized transcriptional activator in wheat. The taabi19-b1 null mutants obtained by EMS performed down-regulation of starch synthesis, shorter grain length and lower thousand grain weight (TGW). Furthermore, we provided TaABI19 could bind to the promoters of TaPBF homology genes and enhance their expression. Haplotype association showed that TaABI19-B1 was significantly associated with TGW. We found that Hap2 and Hap3 were favored and underwent positive selection in China wheat breeding. Less than fifty percent in the modern cultivars conveying favored haplotypes indicates TaABI19 still can be considered as target loci for marker-assisted selection breeding to increase TGW in China.

The trichomes of rice leaves are formed by the differentiation and development of epidermal cells.  Plant trichomes play an important role in stress resistance and protection against direct ultraviolet irradiation.  However, the development of rice trichomes remains poorly understood.  In this study, we conducted ethylmethane sulfonate (EMS)-mediated mutagenesis on the wild-type (WT) indica rice ‘Xida 1B’.  Phenotypic analysis led to the screening of a mutant that is defective in trichome development, designated lhl1 (less hairy leaf 1).  We performed map-based cloning and localized the mutated gene to the 70-kb interval between the molecular markers V-9 and V-10 on chromosome 2.  The locus LOC_Os02g25230 was identified as the candidate gene by sequencing.  We constructed RNA interference (LHL1-RNAi) and overexpression lines (LHL1-OE) to verity the candidate gene.  The leaves of the LHL1-RNAi lines showed the same trichome developmental defects as the lhl1 mutant, whereas the trichome morphology on the leaf surface of the LHL1-OE lines was similar to that of the WT, although the number of trichomes was significantly higher.  Quantitative real-time PCR (RT-qPCR) analysis revealed that the expression levels of auxin-related genes and positive regulators of trichome development in the lhl1 mutant were down-regulated compared with the WT.  Hormone response analysis revealed that LHL1 expression was affected by auxin.  The results indicate that the influence of LHL1 on trichome development in rice leaves may be associated with an auxin pathway.

This study investigated cold plasmas for multiple biological applications.  Our previous work has found dielectric barrier discharge plasma improves chicken sperm quality.  The number of Sertoli cells (SCs) decides spermatogenesis.  However, whether cold plasma can regulate SC proliferation remains unclear.  This study explored the effects of cold plasma on immature chicken SC proliferation and the regulation mechanism.  Results showed that cold plasma exposure at 2.4 W for 30 s twice with an interval of 6 h produced (P<0.05) the maximum SC viability, cell growth, and cell cycle progression.  SC proliferation-promoting effect of cold plasma treatment was regulated by increasing (P<0.05) the adenosine triphosphate production and the respiratory enzyme activity in the mitochondria.  This process was potentially mediated by the adenosine monophosphate-activated protein kinase (AMPK)–mammalian target of rapamycin (mTOR) signaling pathway, which was regulated by the microRNA (miRNA) targeting regulation directly and by the intracellular reactive oxygen species homeostasis indirectly.  The cold plasma treatment increased (P<0.01) the miR-7450-5p expression and led to a decreased (P<0.01) AMPKα1 level.  On the other hand, miR-100-5p expression was reduced (P<0.05) and led to an increased (P<0.05) mTOR level in SCs.  A single-stranded synthetic miR-7450-5p antagomir and a double-stranded synthetic miR-100-5p agomir reduced (P<0.05) the SC proliferation.  However, this could be ameliorated (P<0.05) by the cold plasma treatment.  Our findings suggest that appropriate cold plasma treatment provides a safe strategy to improve SC proliferation, which is beneficial to elevating male chicken reproductive capacity.

Brassica napus is an important cash crop broadly grown for the vegetable and oil values.  Yellow-seeded B. napus is preferred by breeders due to its improved oil and protein quality, less pigments and lignin compared with the black-seeded counterpart.  This study compared the differences in flavonoid and fatty acid contents between yellow rapeseed from the progenies of B. napus–Sinapis alba somatic hybrids and the black-seeded counterpart using RNA-seq analysis.  Through HPLC-PDA-ESI(−)/MS² analysis, it was found that phenylpropanoids and flavonoids (i.e., isorhamnetin, epicatechin, kaempferol, and other derivatives) in yellow seed were significantly lower than those in black seed.  The fatty acid (FA) content in yellow rapeseed was higher than that in black rapeseed due to the variation of C16:0, C18:0, C18:1, C18:2, and C18:3 contents.  RNA-seq analysis of seeds at four and five weeks after flowering (WAF) indicated that differentially expressed genes (DEGs) between black and yellow rapeseeds were enriched in flavonoid and FA biosynthesis, including BnTT3, BnTT4, BnTT18, and BnFAD2.  Also, genes related to FA biosynthesis, desaturation and elongation (FAD3, LEC1, FUS3, and LPAT2) in yellow seed were up-regulated compared to those in black seed, while genes involved in beta-oxidation cycle (AIM1 and KAT2) of yellow seed were down-regulated compared to those in black seed.  The DEGs related to the variation of flavonoids, phenylpropanoids, and FAs would help improve the knowledge of yellow seed character in B. napus and promote rapeseed improvement.

Plant MYB transcription factors (TFs) play crucial roles in regulating the biosynthesis of flavonoids but current analysis on their role in Zanthoxylum bungeanum Maxim. (ZBM) is far from comprehensive.  In this study, we identified 270 MYB genes in ZBM and divided them into four subfamilies.  The R2R3-MYB (ZbMYB) category contained 251 genes and was classified into 33 subfamilies according to their phylogenetic results and sequence similarity.  These subfamilies included 24 subgroups containing both MYBs of ZBM plants and AtMYBs, and nine subgroups containing only ZBM MYBs or AtMYBs.  ZbMYBs with similar functions clustered into the same subgroup, indicating functional conservation.  The subcellular localization analysis predicted that most ZbMYB genes were found in the nucleus.  The transposed duplications appeared to play a major role in the expansion of the MYB gene family in ZBM.  Through phylogenetic analysis and transcriptome profiling, it was found that 28 ZbMYB genes may regulate the biosynthesis of flavonoids in ZBM, and these genes expression presented distinct temporal and spatial expression patterns.  In different fruit development stages of ZBM, the expression patterns of EVM0042160 and EVM0033809 genes obtained by qRT-PCR analysis are very similar to the flavonoid and anthocyanin content curves in ZBM.  Further correlation analysis showed that the content of flavonoids in different fruit development stages and the transcript abundance levels of 28 ZbMYB genes have different degrees of correlation relationship.  These results indicated that the ZbMYB genes might be involved in the flavonoid metabolic pathway.  This comprehensive and systematic analysis of MYB family genes provided a solid foundation for further functional analysis of MYB TFs in ZBM.

Legume cultivars affect N uptake, component crop growth, and soil physical and chemical characteristics in maize–legume intercropping systems.  However, how belowground interactions mediate root growth, N fixation, and nodulation of different legumes to affect N uptake is still unclear.  Hence, a two-year experiment was conducted with five planting patterns, i.e., maize–soybean strip intercropping (IMS), maize–peanut strip intercropping (IMP), and corresponding monocultures (monoculture maize (MM), monoculture soybean (MS), and monoculture peanut (MP)), and two N application rates, i.e., no N fertilizer (N–) and conventional N fertilizer (N+), to examine relationships between N uptake and root distribution of crops, legume nodulation and soil N availability.  Results showed that the averaged N uptake per unit area of intercrops was significantly lower than the corresponding monocultures.  Compared with the monoculture system, the N uptake of the intercropping systems increased by 31.7–45.4% in IMS and by 7.4–12.2% in IMP, respectively.  The N uptake per plant of intercropped maize and soybean significantly increased by 61.6 and 31.8%, and that of intercropped peanuts significantly decreased by 46.6% compared with the corresponding monocultures.  Maize and soybean showed asymmetrical distribution of roots in strip intercropping systems.  The root length density (RLD) and root surface area density (RSAD) of intercropped maize and soybean were significantly greater than that of the corresponding monocultures.  The roots of intercropped peanuts were confined, which resulted in decreased RLD and RSAD compared with the monoculture.  The nodule number and nodule fresh weight of soybean were significantly greater in IMS than in MS, and those of peanut were significantly lower in IMP than in MP.  The soil protease, urease, and nitrate reductase activities of maize and soybean were significantly greater in IMS and IMP than in the corresponding monoculture, while the enzyme activities of peanut were significantly lower in IMP than in MP.  The soil available N of maize and soybean was significantly greater increased in IMS and IMP than in the corresponding monocultures, while that of IMP was significantly lower than in MP.  In summary, the IMS system was more beneficial to N uptake than the IMP system.  The intercropping of maize and legumes can promote the N uptake of maize, thus reducing the need for N application and improving agricultural sustainability.

Organic acids are one of the most important factors influencing fruit flavors. The predominant organic acid in most pear cultivars is malic acid, but the mechanism controlling its accumulation remains unclear. In this study, by comparing gene expression levels and organic acid content, we revealed that the expression of PbPH5, which encodes a P_3A-ATPase, is highly correlated with malic acid accumulation in different pear species, with correlation coefficients of 0.932^**, 0.656^*, 0.900^**, and 0.518^* (^*, P<0.05 or ^**, P<0.01) in Pyrus bretschneideri Rehd., P. communis Linn., P. pyrifolia Nakai., and P. ussuriensis Maxim., respectively. Moreover, the overexpression of PbPH5 in pear significantly increased the malic acid content. In contrast, silencing PbPH5 via RNA interference significantly decreased its transcript level and the pear fruit malic acid content. A subcellular localization analysis indicated that PbPH5 is located in the tonoplast. Additionally, a phylogenetic analysis proved that PbPH5 is a PH5 homolog gene that is clustered with Petunia hybrida, Malus domestica, and Citrus reticulata genes. Considered together, these findings suggest PbPH5 is a functionally conserved gene. Furthermore, the accumulation of malic acid in pear fruits is at least partly related to the changes in PbPH5 transcription levels.

Embryo rescue technology plays an important role in seedless grape breeding.  However, the efficiency of embryo rescue, including the embryo formation, germination, and seedling rates, is closely related to the parental genotypes, degree of abortion, growth medium, and plant growth regulators.  In this study, we investigated the effects of different concentrations of paclobutrazol (PAC), a plant growth regulator, and embryo collection times on the embryo formation, germination, and seedling rates for different hybrid combinations of grape breeding varieties used for their aroma and cold-resistance traits.  The results showed that the different PAC concentrations had varying impacts on the development of ovules and embryos from the different grape varieties.  The embryo formation rates of the ‘Sultanina Rose’בBeibinghong’ and ‘Kunxiang Seedless’בTaishan-2’ crosses were the highest under the 5.1 μmol L^–1 PAC treatment.  The 1.0 μmol L^–1 PAC treatment was optimal for the germination and seedling development of the ‘Sultanina Rose’בBeibinghong’ embryos, whereas the 0.2 μmol L^–1 PAC treatment induced the highest germination rate for the ‘Sultanina Rose’בKunxiang Seedless’ cross.  The optimal sampling times for each cross varied as 39 d after pollination (DAP) for the ‘Flame Seedless’בMuscat Hamburg’ cross, 46 DAP for the ‘Kunxiang Seedless’בBeibinghong’ cross, and 41 DAP for the ‘Ruby Seedless’בBeibinghong’ and ‘Fantasy Seedless’בShuangyou’ crosses.  Moreover, the medium modified with 0.5 g L^–1 of indole-3-butyric acid allowed the malformed seedlings to develop into plantlets and achieve larger progenies.  This study provides a useful basis for further studies into grape embryo rescue and could improve breeding efforts for new seedless grape varieties.

In China, the traditional early and late season double rice (DR) system is declining accompanied by the fast increase of two newly developed cropping systems: ratoon rice (RR) and rice–crawfish (RC).  Three methodologies: economic analysis, emergy evaluation and life cycle assessment (LCA) were employed to evaluate the economics and sustainability of this paddy cropping system change.  Economic analysis indicated that the income and profit of the RC system were far larger than those of RR and DR.  The income to costs ratio of RR and RC increased by 25.5 and 122.7% compared with that of DR, respectively.  RC had the highest emergy input thanks to increasing irrigation water, electricity, juvenile crawfish and forage input while RR showed a lower total emergy and nonrenewable emergy input, such as irrigation water, electricity, fertilizers and pesticides than DR.  The environmental loading ratios decreased by 16.7–50.4% when cropping system changed from DR to RR or from DR to RC while the emergy sustainability indexes increased by 22.6–112.9%.  The life cycle assessment indicated lower potential environmental impacts of RR and RC, whose total environmental impact indexes were 35.0–61.0% lower than that of DR.  Grain yield of RR was comparable with that of DR in spite of less financial and emergy input of RR, but RC had a much lower grain yield (a 53.6% reduction compared to DR).  These results suggested that RR is a suitable cropping system to achieve the food security, economic and environmental goals.

Grain zinc (Zn) and iron (Fe) concentrations and their responses to foliar application of micronutrients in 28 Chinese wheat landraces and 63 cultivars were investigated in a two-year field experiment.  The average grain Zn and Fe concentrations were 41.8 mg kg^–1 (29.0−63.3 mg kg^–1) and 39.7 mg kg^–1 (27.9−67.0 mg kg^–1), respectively.  Compared with cultivars, landraces had greater grain Zn (11.0%) and Fe (4.8%) concentrations but lower harvest index (HI), grain weight per spike (GWS), grain number per spike (GNS) and thousand grain weight (TGW).  Both Zn and Fe concentrations were negatively and significantly correlated with HI, GWS, and GNS, while showed a poor association with TGW, suggesting that lower HI, GWS, and GNS, but not TGW, accounted for higher Zn and Fe concentrations for landraces than for cultivars.  Grain Zn concentrations of both cultivars and landraces significantly increased after foliar Zn spray and the increase was two-fold greater for landraces (12.6 mg kg^–1) than for cultivars (6.4 mg kg^–1).  Foliar Fe spray increased grain Fe concentrations of landraces (3.4 mg kg^–1) and cultivars (1.2 mg kg^–1), but these increases were not statistically significant.  This study showed that Chinese wheat landraces had higher grain Zn and Fe concentrations than cultivars, and greater increases occurred in grain Zn concentration than in grain Fe concentration in response to fertilization, suggesting that Chinese wheat landraces could serve as a potential genetic source for enhancing grain mineral levels in modern wheat cultivars.

Excessive rainfall provides a favorable condition for field mold infection of plants, which triggers field mold (FM) stress.  If FM stress occurs during the late maturation stage of soybean seed, it negatively affects seed yield and quality.  To investigate the responses of soybean seed against FM stress and identify the underlying biochemical pathways involved, a greenhouse was equipped with an artificial rain producing system to allow the induction of mold growth on soybean seed.  The induced quality changes and stress responses were revealed on the levels of both transcriptome and metabolome.  The results showed that soybean seeds produced under FM stress conditions had an abnormal and inferior appearance, and also contained less storage reserves, such as protein and polysaccharide.  Transcriptional analysis demonstrated that genes involved in amino acid metabolism, glycolysis, tricarboxylic acid, β-oxidation of fatty acids, and isoflavone biosynthesis were induced by FM stress.  These results were supported by a multiple metabolic analysis which exhibited increases in the concentrations of a variety of amino acids, sugars, organic acids, and isoflavones, as well as reductions of several fatty acids.  Reprogramming of these metabolic pathways mobilized and consumed stored protein, sugar and fatty acid reserves in the soybean seed in order to meet the energy and substrate demand on the defense system, but led to deterioration of seed quality.  In general, FM stress induced catabolism of storage reserves and diminished the quality of soybean seed in the field.  This study provides a more profound insight into seed deterioration caused by FM stress.

The gray leaf spot caused by Cercospora zeina has become a serious disease in maize in China.  The isolates of C. zeina from Yunnan, Sichuan, Guizhou, Hubei, Chongqing, Gansu, and Shaanxi were collected.  From those, 127 samples were used for genetic diversity analysis based on inter-simple sequence repeat (ISSR) and 108 samples were used for multi-gene sequence analysis based on five gene fragments.  The results indicated that populations of C. zeina were differentiated with a relatively high genetic level and were classified into two major groups and seven subgroups.  The intra-population genetic differentiation of C. zeina is the leading cause of population variation in China, and inter-population genetic similarity is closely related to the colonization time and spread direction.  The multi-gene sequence analysis of C. zeina isolates demonstrated that there were nine haplotypes.  Genetic diversity and multi-gene sequence revealed that Yunnan population of C. zeina, the earliest colonizing in China, had the highest genetic and haplotype diversity and had experienced an expansion event.  With the influence of the southwest monsoon in the Indian Ocean, C. zeina from Yunnan gradually moved to Sichuan, Guizhou, Shaanxi, Gansu, and Chongqing.  Meanwhile, C. zeina was transferred directly from the Yunnan into the Hubei Province via seed and then came into Shaanxi, Henan, and Chongqing along with the wind from Hubei.

As a critical food crop, sweetpotato (Ipomoea batatas (L.) Lam.) is widely planted all over the world, but it is deeply affected by Sweetpotato Virus Disease (SPVD).  The present study utilized short tandem target mimic (STTM) technology to effectively up-regulate the expression of laccase (IbLACs) by successfully inhibiting the expression of miR397.  The upstream genes in the lignin synthesis pathway were widely up-regulated by feedback regulation, including phenylalanine ammonialyase (PAL), 4-coumarate-CoAligase (4CL), hydroxycinnamoyl CoA:shikimatetransferase (HTC), caffeicacid O-methyltransferase (COMT), and cinnamyl alcohol dehydrogenase (CAD).  Meanwhile, the activities of PAL and LAC increased significantly, finally leading to increased lignin content.  Lignin deposition in the cell wall increased the physical defence ability of transgenic sweetpotato plants, reduced the accumulation of SPVD transmitted by Bemisia tabaci (Gennadius), and promoted healthy sweetpotato growth.  The results provide new insights for disease resistance breeding and green production of sweetpotato. 

Litchi chinensis Sonn is widely cultivated in subtropical regions and has an important economic value.  A high-density genetic map is a valuable tool for mapping quantitative trait loci (QTL) and marker-assisted breeding programs.   In this study, a single nucleotide polymorphism (SNP)-based high-density linkage map was constructed by a genotyping-by-sequencing (GBS) protocol using an F1 population of 178 progenies between two commercial litchi cultivars, ‘Ziniangxi’ (dwarf) and ‘Feizixiao’ (vigorous).  The genetic map consisted of 3 027 SNP markers with a total length of 1 711.97 cM in 15 linkage groups (LGs) and an average marker distance of 0.57 cM.  Based on this high-density linkage map and three years of phenotyping, a total of 37 QTLs were detected for eight dwarf-related traits, including length of new branch (LNB), diameter of new branch (DNB), length of common petiole (LCP), diameter of common petiole (DCP), length of internode (LI), length of single leaf (LSL), width of single leaf (WSL), and plant height (PH).  These QTLs could explain 8.0 to 14.7% (mean=9.7%) of the phenotypic variation.  Among them, several QTL clusters were observed, particularly on LG04 and LG11, which might show enrichment for genes regulating the dwarf-related traits in litchi.  There were 126 candidate genes identified within the QTL regions, 55 of which are differentially expressed genes by RNA-seq analysis between ‘Ziniangxi’ and ‘Feizixiao’.  These DEGs were found to participate in the regulation of cell development, material transportation, signal transduction, and plant morphogenesis, so they might play important roles in regulating plant dwarf-related traits.  The high-density genetic map and QTLs identification related to dwarf traits can provide a valuable genetic resource and a basis for marker-assisted selection and genomic studies of litchi.