Small auxin up RNA (SAUR) is a large gene family that is widely distributed among land plants.  In this study, a comprehensive analysis of the SAUR family was performed in sweet cherry, and the potential biological functions of PavSAUR55 were identified using the method of genetic transformation.  The sweet cherry genome encodes 86 SAUR members, the majority of which are intron-less.  These genes appear to be divided into seven subfamilies through evolution.  Gene duplication events indicate that fragment duplication and tandem duplication events occurred in the sweet cherry.  Most of the members mainly underwent purification selection pressure during evolution.  During fruit development, the expression levels of PavSAUR16/45/56/63 were up-regulated, and conversely, those of PavSAUR12/61 were down-regulated.  Due to the significantly differential expressions of PavSAUR13/16/55/61 during the fruitlet abscission process, they might be the candidate genes involved in the regulation of physiological fruit abscission in sweet cherry.  Overexpression of PavSAUR55 in Arabidopsis produced earlier reproductive growth, root elongation, and delayed petal abscission.  In addition, this gene did not cause any change in the germination time of seeds and was able to increase the number of lateral roots under abscisic acid (ABA) treatment.  The identified SAURs of sweet cherry play a crucial role in fruitlet abscission and will facilitate future insights into the mechanism underlying the heavy fruitlet abscission that can occur in this fruit crop.

Monoclonal antibodies (mAbs) are widely used in virus research and disease diagnosis.  The nucleoprotein (NP) of influenza A virus (IAV) plays important roles in multiple stages of the virus life cycle.  Therefore, generating conserved mAbs against NP and characterizing their properties will provide useful tools for IAV research.  In this study, two mAbs against the NP protein, 10E9 and 3F3, were generated with recombinant truncated NP proteins (NP-1 and NP-2) as immunogens.  The heavy-chain subclass of both 10E9 and 3F3 was determined to be IgG2α, and the light-chain type was κ.  Truncation and site-specific mutation analyses showed that the epitopes of mAbs 10E9 and 3F3 were located in the N terminal 84–89 amino acids and the C terminal 320–324 amino acids of the NP protein, respectively.  We found that mAbs 10E9 and 3F3 reacted well with the NP protein of H1–H15 subtypes of IAV.  Both 10E9 and 3F3 can be used in immunoprecipitation assay, and 10E9 was also successfully applied in confocal microscopy.  Furthermore, we found that the 10E9-recognized ₈₄SAGKDP₈₉ epitope and 3F3-recognized ₃₂₀ENPAH₃₂₄ epitope were highly conserved in NP among all avian and human IAVs.  Thus, the two mAbs we developed could be used as powerful tools in the development of diagnostic methods of IAV, and also surely promote the basic research in understanding the replication mechanisms of IAV.

    Drought is a multifaceted stress condition that inhibits crop growth. Seed germination is one of the critical and sensitive stages of plants, and its process is inhibited or even entirely prevented by drought. Polyamines (PAs) are closely associated with plant resistance to drought stress and seed germination. However, little is known about the effect of PA on the seed germination of wheat under drought stress. This study investigated the involvement of PAs in regulating wheat seed germination under drought stress. Six wheat genotypes differing in drought resistance were used, and endogenous PA levels were measured during seed germination under different water treatments. In addition, external PA was used for seed soaking and the variation of hormones, total soluble sugar and starch were measured during the seed germination under different water treatments. These results indicated that the free spermidine (Spd) accumulation in seeds during the seed germination period favored wheat seed germination under drought stress; however, the free putrescine (Put) accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress. In addition, seed soaking in Spd and spermine (Spm) significantly relieved the inhibition of seed germination by drought stress; however, soaking seeds in Put had no significant effect on seed germination under drought. External Spd and Spm significantly increased the endogenous indole-3-acetic acid (IAA), zeatin (Z)+zeatin riboside (ZR), abscisic acid (ABA), and gibberellins (GA) contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination. This may promote wheat seed germination under drought stress. In conclusion, free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.

Although plastic-covered ridge and furrow planting (RF) has been reported to produce substantial increases in the grain weight of winter wheat, the underlying mechanism is not yet understood. The present study used two cultivars, Xinong 538 and Zhoumai 18, and RF and traditional flatten planting (TF, control) with the objective of investigating the effect of RF on wheat grain filling and the possible relationship of hormonal changes in the wheat grains under RF to grain filling. The results indicated that RF significantly increased the grain weight, although the effects on grain filling were different: RF significantly increased the grain-filling rate and grain weight of inferior grains, whereas RF had no significant effect on grainfilling rate and grain weight of superior grains. The ?nal grain weight of inferior grains under RF was 39.1 and 50.7 mg for Xinong 538 and Zhoumai 18, respectively, 3.6 and 3.4 mg higher than the values under TF. However, the final grain weight of superior grains under RF was only 0.6 and 0.8 mg higher than under TF for Xinong 538 and Zhoumai 18, respectively. RF significantly decreased the ethylene and gibberellic acid content in the inferior grains and increased the indole-3-acetic acid, abscisic acid and zeatin + zeatin riboside content in the inferior grains; however, no significant difference between RF and TF was observed for the hormonal content in the superior grains. Based on these results, we concluded that RF significantly modulated hormonal changes in the inferior grains and, thus, affected the grain filling and grain weight of the inferior grains; in contrast, RF had no significant effect on grain filling, grain weight and hormonal changes in the superior wheat grains.

Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching (plastic film on sowing, as well as plastic film on flat soil and hole sowing) and chemicals (a drought resistant agent and a waterretaining agent) on growth, photosynthetic rate, yield, and water use efficiency (WUE) of spring millet (Setaria italica L.). The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage (late growth advantage). However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage (early growth advantage). Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plasticcovered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.

Leaves and glumes act as lateral organs and have essential effects on photosynthesis and seed morphology, thus affecting yield.  However, the molecular mechanisms controlling their polarity development in rice is still worth further analysis.  Here, we isolated a polarity defect of lateral organs 1 (pdl1) mutant in rice, which exhibits twisted/filamentous-shaped leaves and cracked/filamentous-shaped lemmas caused by defects in polarity development.  PDL1 encodes a SUPPRESSOR OF GENE SILENCING 3 protein localized in the cytoplasm granules.  PDL1 is expressed in the shoot apical meristem, inflorescence meristem, floral meristem, and lateral organs including leaf and floral organs.  PDL1 is involved in the synthesis of tasiR-ARF, which may subsequently modulate the expression of OsARFs.  Meanwhile, the expression of abaxial miR165/166 and the adaxial identity genes OSHBs was increased and decreased significantly, respectively.  The results of this study clarified the molecular mechanism that the PDL1-mediated tasiR-ARF synthesis regulates the lateral organ polarity development in rice.

Drought is becoming a common threat to crop production.  To combat this stress and ensure global food security, the identification and utilization of excellent drought-resistant genes are crucial for developing drought-resistant crop varieties.  However, sugar transporters are known to be involved in stress tolerance in many plants, while the sugar transporter gene family of Tartary buckwheat has not been systematically analyzed yet.  In this study, 140 sugar transporter genes were identified from the ‘Pinku’ Tartary buckwheat genome and classified into ten subfamilies.  Structural analysis showed that subfamily SGB/pGlcT had the highest number of introns compared to other subfamilies, and abundant abiotic stress-related cis-acting elements existed in the promoter region.  Collinear analysis revealed that FtSUT7, FtSTP28, FtPLT1, and FtINT2 genes are relatively ancient.  The expression of sugar transporter genes was screened under various abiotic stresses which revealed the association of stress tolerance with different sugar transporter genes, i.e., FtERD23, FtINT2, FtpGlcT2, and FtSTP27.  Further, it was observed that the overexpression of FtERD23 maintains osmotic pressure through glucose transport, which may enhance drought stress tolerance.  Moreover, gene co-expression analyses using WGCNA and FCMA identified six transcription factors that may regulate FtERD23 expression and are involved in plant drought tolerance.  In summary, this systematic analysis provides a theoretical basis for further functional characterization of sugar transporter genes to improve drought tolerance in Tartary buckwheat and its related species.

Pear anthracnose, caused by Colletotrichum fructicola, is a devastating disease that seriously affects most pear varieties, thereby compromising their yield and quality. However, effective control of this pathogen is lacking. Moreover, the critical resistance responses to C. fructicola in pear are unknown. To investigate these resistance mechanisms of pear against Colletotrichum fructicola, transcriptomic and metabolomic were performed and analyzed in pear anthracnose-resistant pear variety ‘Seli’ and the susceptible variety ‘Cuiguan’ after infection with C. fructicola, respectively. The differentially expressed genes and differentially accumulated metabolites (DAMs) were mainly related to metabolism and secondary metabolite synthetic pathways, including alpha-linoleic acid metabolism, phenylalanine biosynthesis metabolism, unsaturated fatty acids biosynthesis, and amino acids and derivatives biosynthesis etc. In particular, the accumulation of unsaturated fatty acids, amino acids and derivatives, such as linoleic acid and derivatives, lauric acid, N-acetyl-L-glutamic acid and L-proline was significantly increased in the resistant pear variety ‘Seli’ upon C. fructicola infection, while the amino acids of oxiglutatione and N-acetyl-L-glutamic acid, as well as the proanthocyanidins were significantly decreased in susceptible pear variety ‘Cuiguan’ upon C. fructicola infection, indicating that these metabolites were responsible for the different levels of resistance to anthracnose in ‘Seli’ and ‘Cuiguan’. Overall, our results provided new insights into pear anthracnose resistance regulation, and this may assist in developing new strategies to control pear anthracnose, as well as in breeding anthracnose-resistant varieties.

Tartary buckwheat (Fagopyrum tataricum), an under-utilized pseudocereal, has important nutritional and pharmaceutical properties and is resistant to drought and nutrient deficiency.  However, this environmentally friendly crop is sensitive to salt stress that can result in water loss, stomatal closure, affect photosynthesis and metabolism, and reduce yield and quality of Tartary buckwheat.  Thus, it is important to understand the mechanism of salt stress tolerance in buckwheat. In this study, we identified a locus including 35 candidate genes on chromosome 2 that is significantly associated with salt tolerance of Tartary buckwheat by genome-wide association analysis (GWAS).  Transcriptome analysis revealed that the serine/threonine-protein kinase Aurora-3 (FtAUR3) family gene was up-regulated in response to salt stress.  The deletion of a single nucleotide in the FtAUR3 promoter leads to increased FtAUR3 expression and enhanced salt tolerance in Tartary buckwheat.  Overexpression of FtAUR3 in buckwheat hairy roots leads to the accumulation of flavonoids, including rutin and cinnamic acid, as well as the induction of the expression of flavonoid biosynthesis genes, such as PAL, C4H, F3H and F3’H, under salt stress.  In addition, it was shown that over-expression of FtAUR3 in Arabidopsis thaliana induced the expression of salt-resistant genes (SOS1, AVP1, etc.) and enhanced salt tolerance compared to wild type plants.  Furthermore, under salt stress, FtAUR3 can significantly enhances the levels of reactive oxygen species pathway components, including superoxide dismutase, catalase, and peroxidase, thereby improving plant salt tolerance.  Thus, we demonstrated that FtAUR3 interacts with the critical enzyme FtGAPB in the ROS pathway, suggesting a potential mechanism through which FtAUR3 contributes to ROS signaling.  Taken together, these results demonstrated that FtAUR3 may play a critical positive role in Tartary buckwheat resistance against salt stress.