Previous studies have revealed the miR164 family and the miR164-targeted NAC transcription factor genes in rice (Oryza sativa) and Arabidopsis that play versatile roles in developmental processes and stress responses.  In wheat (Triticum aestivum L.), we found nine genetic loci of tae-miR164 (tae-MIR164 a to i) producing two mature sequences that down-regulate the expression of three newly identified target genes of TaNACs (TaNAC1, TaNAC11, and TaNAC14) by the cleavage of the respective mRNAs.  Overexpression of tae-miR164 or one of its target genes (TaNAC14) demonstrated that the miR164-TaNAC14 module greatly affects root growth and development and stress (drought and salinity) tolerance in wheat seedlings, and TaNAC14 promotes root growth and development in wheat seedlings and enhances drought tolerance, while tae-miR164 inhibits root development and reduces drought and salinity tolerance by down-regulating the expression of TaNAC14.  These findings identify the miR164-TaNAC14 module as well as other tae-miR164-regulated genes which can serve as new genetic resources for stress-resistance wheat breeding.

Rosa sterilis S. D. Shi is an important economic tree in China that produces fruits with high nutritional and medicinal value.  Many of R. sterilis’ organs are covered with different types of trichomes or prickles that directly affect fruit appearance and plant management.  This study used RNA sequencing technology to analyze the transcriptomes of two parts of the inflorescence branch, namely inflorescence stems with flagellated trichomes and pedicels with both flagellated and glandular trichomes.  Comparative transcriptomic analysis showed that many transcription factors (TFs) are potentially involved in the formation and development of trichomes.  The accumulation of RsETC1, a TF of the R3-MYB family, was significantly higher in inflorescence stems than in pedicels; quantitative reverse transcription PCR (qRT-PCR) verified that its expression was significantly higher in inflorescence stems than in pedicels during the first three development stages, indicating its inhibitory action on the initiation of glandular trichomes in R. sterilis.  The mRNA level of RsETC1 accumulated to significantly higher levels in trichomeless tissues than in tissues with trichromes, suggesting that this gene may inhibit the formation of trichomes in R. sterilis.  Over-expression of RsETC1 in Arabidopsis resulted in glabrous phenotypes, and the expression of trichome-related endogenous genes, except for TTG1, was markedly reduced.  In addition, the contents of the phytohormones jasmonic acid (JA), gibberellin A3 (GA₃), and cytokinins (CKs) in pedicels were significantly higher than those in inflorescence stems, and the expression patterns of the genes related to hormone biosynthesis and signal transduction presented consistent responses, suggesting that the transduction of these hormones might be crucial for trichome initiation and development.  These data provide a new perspective for revealing the molecular mechanism of trichome formation in R. sterilis.

North China Plain (NCP) is the primary winter wheat production region in China, characterized by smallholder farming systems.  Whereas the winter wheat average yield of smallholder farmers is currently low, the yield potential and limiting factors driving the current yield gap remain unclear.  Therefore, increasing the wheat yield in NCP is essential for the national food security.  This study monitored wheat yield, management practices and soil nutrient data in 132 farmers’ fields of Xushui County, Baoding City, Hebei Province during 2014–2016.  These data were analyzed using variance and path analysis to determine the yield gap and the contribution of yield components (i.e., spikes per hectare, grain number per spike and 1 000-grain weight) to wheat yield.  Then, the limiting factors of yield components and the optimizing strategies were identified by a boundary line approach.  The results showed that the attainable potential yield for winter wheat was 10 514 kg ha^–1.  The yield gaps varied strongly between three yield groups (i.e., high, middle and low), which were divided by yield level and contained 44 farmers in each group, and amounted to 2 493, 1 636 and 814 kg ha^–1, respectively.  For the three yield components, only spikes per hectare was significantly different (P<0.01) among the three yield groups.  For all 132 farmers’ fields, correlation between yield and spikes per hectare (r=0.51, P<0.01), was significantly positive, while correlations with grain number per spike (r=–0.16) and 1 000-grain weight (r=–0.10) were not significant.  The path analysis also showed that the spikes per hectare of winter wheat were the most important component to the wheat yield.  Boundary line analysis showed that seeding date was the most limiting factor of spikes per hectare with the highest contribution rate (26.7%), followed by basal N input (22.1%) and seeding rate (14.5%), which indicated that management factors in the seeding step were the most important for affecting spikes per hectare.  For desired spikes per hectare (>6.598×106 ha^–1), the seeding rate should range from 210–300 kg ha^–1, seeding date should range from 3th to 8th October, and basal N input should range from 90–180 kg ha^–1.  Compared to these reasonable ranges of management measures, most of the farmers’ practices were not suitable, and both lower and higher levels of management existed.  It is concluded that the strategies for optimizing yield components could be achieved by improving wheat seeding quality and optimizing farmers’ nutrient management practices in the NCP.

As an important food crop and oil crop, soybean (Glycine max [L.] Merr.) is capable of nitrogen-fixing by root nodule.  Previous studies showed that GmNMH7, a transcription factor of MADS-box family, is associated with nodule development, but its specific function remained unknown.  In this study, we found that GmNMH7 was specifically expressed in root and nodule and the expression pattern of GmNMH7 was similar to several genes involved in early development of nodule (GmENOD40-1, GmENOD40-2, GmNFR1a, GmNFR5a, and GmNIN) after rhizobia inoculation.  The earlier expression peak of GmNMH7 compared to the other genes (GmENOD40-1, GmENOD40-2, GmNFR1a, GmNFR5a, and GmNIN) indicated that the gene is related to the nod factor (NF) signaling pathway and functions at the early development of nodule.  Over-expression of GmNMH7 in hairy roots significantly reduced the nodule number and the root length.  In the transgenic hairy roots, over-expression of GmNMH7 significantly down-regulated the expression levels of GmENOD40-1, GmENOD40-2, and GmNFR5α.  Moreover, the expression of GmNMH7 could respond to abscisic acid (ABA) and gibberellin (GA₃) treatment in the root of Zigongdongdou seedlings.  Over-expressing GmNMH7 gene reduced the content of ABA, and increased the content of GA₃ in the positive transgenic hairy roots.  Therefore, we concluded that GmNMH7 might participate in the NF signaling pathway and negatively regulate nodulation probably through regulating the content of GA₃.
 

Plant-pathogenic Xanthomonas infects a wide variety of host plants and causes many devastating diseases on crops.  Transcription activator-like effectors (TALEs) are delivered by a type III secretion system (T3SS) of Xanthomonas into plant nuclei to directly bind specific DNA sequences (TAL effector-binding elements, EBEs) on either strand of host target genes with an unique modular DNA-binding domain and to bidirectionally drive host gene transcription.  The target genes in plants consist of host susceptibility (S) genes promoting disease (ETS) and resistance (R) genes triggering defense (ETI).  Here we generally summarized the discovery of TALEs in Xanthomonas species, their functions in bacterial pathogenicity in plants and their target genes in different host plants, and then focused on the newly revealed modes of protein action in triggering or suppressing plant defense.

Our previous studies showed that the anti-inflammatory effects of Paeonia lactiflora roots extract may be mediated, at least in part, through its gallic acid content, and this effect may be regulated in part by an inhibition on cAMP-phosphodiesterase (PDE). To explore the anti-inflammatory effect and mechanism, the influence of gallic acid on neutrophils PDE4 activity and expression, TNF-α and IL-6 content and rat arthritis model were further studied. PDE4 activity and gene express were calculated respectively by substrate cAMP change examined with HPLC and real-time RT-PCR. The concentration of IL-6 and TNF-α in supernatant were assayed by ELISA method. Model of rat arthritis was caused by complete Freund’s adjuvant. Results showed that gallic acid had a dose-dependent restraint on PDE4 activity of neutrophils in vitro, promoted significantly PDE4A expression (P<0.01), and had no influence on the expressions of PDE4B and 4D. However, PDE4C expression was not detected. Gallic acid could promote IL-6 release (P<0.05), and inhibit TNF-α release of neutrophils (P<0.05). The experiment in vivo showed that gallic acid had obvious restraint on local inflammation of animal model (P<0.05). Therefore, the anti-inflammatory effect of gallic acid may be mediated in part through an inhibition on PDE4 activity and further an increase of IL-6 and a decrease of TNF-α of neutrophils, and this effect seemed to have no relationship with PDE4 expression.

Luteolin is an active ingredient found early from Folium perillae and Flos lonicerae, and has a specific inhibition on phosphodiesterase 4 (PDE4) activity in vitro. Researches show luteolin has pharmacological effects of anti-inflammation, anti-anaphylaxis, antitumor, antioxidant, protection of nervous system and so on, and has mainly been used for the treatment of respiratory inflammatory diseases, cancer and cardiovascular disease in clinic. PDE4, specific to hydrolyze cyclic AMP (cAMP), is considered to be a new anti-inflammatory target due to the decisive role on cAMP signal in inflammatory cells such as neutrophils. In order to explore the anti-inflammatory mechanism, we further studied the effects of luteolin on the activity and expression of PDE4, the expression of lymphocyte function-associated antigen-1 (LFA-1) and macrophage-1 (MAC-1) in neutrophils, and the adhesion of neutrophils and endothelial cells. The results showed that luteolin had a dose-dependent inhibition on both bare PDE4 activity and PDE4 in cultured neutrophils, and had an obviously promotive effect on gene expressions of PDE4A, 4B and 4D in later period. Luteolin had a significant inhibitory effect on neutrophils adhesion and LFA-1 expression in early stage, and had no obvious effect on MAC-1 expression. Therefore, luteolin can inhibit LFA-1 expression of neutrophils, then inhibit the adhesion of neutrophils and endothelial cells, and the mechanism is at least related with the inhibition of PDE4 activity.

Wheat (Triticum aestivum L.) often experiences photoinhibition due to strong light during the grain filling stage. As such, increasing the tolerance of wheat to photoinhibition is very desirable in breeding efforts focused on increasing grain yields. Previous reports have suggested that PROTON GRADIENT REGULATION 5 (PGR5) plays a central role in the generation of a proton gradient across the thylakoid membrane (DpH) and in acclimation to high light intensity conditions. Three PGR5 homoeologues were isolated from wheat, and mapped onto chromosomes 7A, 7B and 7D, respectively. The TaPGR5s shared highly similar genomic sequences and gene structures. The transcripts of TaPGR5s were found to be abundantly expressed in the flag leaves, and were transiently up-regulated by treatment with high light. High light treatment inhibited the net photosynthetic rate (Pn) and the maximal quantum yield of photosystem II (Fv/Fm). Further, these inhibitions were more evident in the leaves with reduced expression of TaPGR5s achieved using virus-induced gene silencing methods. Moreover, reducing TaPGR5 expression impaired the induction of non-photochemical quenching (NPQ), which caused more severe cell membrane damage and lipid peroxidation in high light. Additionally, we observed that TaPGR5s transcripts were more abundantly expressed in the wheat genotypes with higher ms-delayed light emission (ms-DLE), a value reflecting transthylakoid DpH. These results suggested that TaPGR5s play important roles in the tolerance of wheat to photoinhibition.

Phytic acid (PA) is the main storage form of phosphorus (P) in seeds. It can form insoluble complexes with microelements, thereby reducing their bioavailability for animals. Identification of quantitative trait loci (QTLs) associated with grain PA concentration (PAC) is essential to improve this trait without affecting other aspects of grain nutrition such as protein content. Using a recombinant inbred line (RIL) population, we mapped QTL for grain PAC, as well as grain nitrogen concentration (NC) and P concentration (PC) in maize under two N conditions in 2 yr. We detected six QTLs for PAC. The QTL for PAC on chromosome 4 (phi072-umc1276) was identified under both low-N and high-N treatments, and explained 13.2 and 15.4% of the phenotypic variance, respectively. We identified three QTLs for grain NC, none of which were in the same region as the QTLs for PAC. We identified two QTLs for PC in the low-N treatment, one of which (umc1710-umc2197) was in the same interval as the QTL for PAC under high-N conditions. These results suggested that grain PAC can be improved without affecting grain NC and inorganic PC.