Virus-induced gene silencing (VIGS) and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) systems are effective technologies for rapid and accurate gene function verification in modern plant biotechnology.  However, the investigation of gene silencing and editing in radish remains limited.  In this study, a bleaching phenotype was generated through the knockdown of RsPDS using tobacco rattle virus (TRV)- and turnip yellow mosaic virus (TYMV)-mediated gene silencing vectors.  The TYMV-mediated gene silencing efficiency was higher than the TRV-based VIGS system in radish.  The expression level of RsPDS was significantly inhibited using VIGS in ‘NAU-067’ radish leaves.  The rootless seedlings of ‘NAU-067’ were infected with Agrobacterium rhizogenes using the 2300GN-Ubi-RsPDS-Cas9 vector with two target sequences.  Nine adventitious roots were blue with GUS staining, and four of these adventitious roots were edited at target sequence 1 of the RsPDS gene as indicated by Sanger sequencing.  Furthermore, albino lines were generated with A. tumefaciens-mediated transformation of radish cotyledons.  Five base substitutions and three base deletions occurred at target sequence 2 in Line 1, and three base insertions and three base substitutions occurred at target sequence 1 in Line 2.  This study shows that VIGS and CRISPR/Cas9 techniques can be employed to precisely verify the biological functions of genes in radish, which will facilitate the genetic improvement of vital horticultural traits in radish breeding program

The effect of nitrogen (N) fertilizer on the development of maize kernels has yet to be fully explored.  MicroRNA-mRNA analyses could help advance our understanding of how kernels respond to N.  This study analyzed the morphological, physiological, and transcriptomic changes in maize kernels under different N rates (0, 100, 200, and 300 kg ha^–1).  The result showed that increasing N application significantly increased maize grains’ fresh and dry weight until N reached 200 kg ha^–1.  Higher levels of indole-3-acetic acid, cytokinin, gibberellin, and a lower level of ethylene were associated with increased N applications.  We obtained 31 differentially expressed genes (DEGs) in hormone synthesis and transduction, and 9 DEGs were regulated by 14 differentially expressed microRNAs (DEMIs) in 26 pairs.  The candidate DEGs and DEMIs provide valuable insight for manipulating grain filling under different N rates.

3´,5´-Cyclic adenosine monophosphate (cAMP) is an important metabolite that is specifically enriched in jujube. However, the effect of cAMP on jujube cellular responses has not been comprehensively studied. Here, we established jujube cell suspension cultures and investigated the calcium influx in response to cAMP treatment through protoplast isolation and fluorescence intensity. Firstly, cAMP treatment could promote jujube growth and increase the content of endogenous cAMP. Using transcriptome analysis with transgenic Arabidopsis plants overexpressing adenylate cyclase (ZjAC) as a positive control, we identified 60 calcium-related differential expressed genes (DEGs) that contributed to the calcium signaling and inter- or intra-cellular responses. Pharmacological treatments such as cAMP and the calcium ionophore A23187 could induce ZjAC expression, the accumulation of cAMP and calcium influx in jujube cells, while ethylene glycol tetraacetic acid (EGTA) or bithionol treatment inhibited these changes. Moreover, the calcium channels and transporters in calcium influx, such as the ZjCNGC2 channel and the mitogen activated protein (MAP) kinase pathway, could be activated by cAMP treatment. In summary, our findings demonstrated that cAMP biosynthesis is dependent on calcium influx and the amplifying effect between calcium and cAMP may be involved in intracellular signal induction, which might contribute to the growth and development of jujube.

Rice direct seeding has the significant potential to save labor and water, conserve environmental resources, and reduce greenhouse gas emissions tremendously.  Therefore, rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.  Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice (DSR) production.  This study used a permanent mapping population with 144 recombinant inbred lines (RILs) and 2 828 bin-markers to detect quantitative trait loci (QTLs) associated with mesocotyl length in 2019 and 2020.  The mesocotyl lengths of the rice RILs and their parents, Lijiangxintuanheigu (LTH) and Shennong 265 (SN265), were measured in a growth chamber at 30°C in a dark environment.  A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2), 2(4), 3(2), 4, 5, 6, 7, 9, 11(2), and 12.  Seven of these QTLs, including qML1a, qML1b, qML2d, qML3a, qML3b, qML5, and qML11b, were reproducibly detected in both years via the interval mapping method.  The major QTL, qML3a, was reidentified in two years via the composite interval mapping method.  A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb, respectively.  Thirteen predicted genes within a relatively small genetic interval (88.18 kb) of the major mesocotyl elongation QTL, qML3a, were more thoroughly analyzed.  Finally, the coding DNA sequence variations among SN265, LTH, and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.  This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.  Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.  In conclusion, these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.  This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.

Flesh firmness (FF) is an important and complex trait for melon breeders and consumers.  However, the genetic mechanism underlying FF is unclear.  Here, a soft fruit melon (P5) and a hard fruit melon (P10) were crossed to generate F₂, and the FF and fruit-related traits were recorded for two years.  By performing quantitative trait locus (QTL) specific-locus amplified fragment (SLAF) (QTL-SLAF) sequencing and molecular marker-linkage analysis, 112 844 SLAF markers were identified, and 5 919 SNPs were used to construct a genetic linkage map with a total genetic distance of 1 356.49 cM.  Ten FF- and fruit-related QTLs were identified.  Consistent QTLs were detected for fruit length (FL) and fruit diameter (FD) in both years, and QTLs for single fruit weight (SFW) were detected on two separate chromosomes in both years.  For FF, the consistent major locus (ff2.1) was located in a 0.17-Mb candidate region on chromosome 2.  Using 429 F₂ individuals derived from a cross between P5 and P10, we refined the ff2.1 locus to a 28.3-kb region harboring three functional genes.  These results provide not only a new candidate QTL for melon FF breeding but also a theoretical foundation for research on the mechanism underlying melon gene function.

As important yield-related traits, thousand-grain weight (TGW), grain number per spike (GNS) and grain weight per spike (GWS) are crucial components of wheat production.  To dissect their underlying genetic basis, a double haploid (DH) population comprised of 198 lines derived from 8762/Keyi 5214 was constructed.  We then used genechip to genotype the DH population and integrated the yield-related traits TGW, GNS and GWS for QTL mapping.  Finally, we obtained a total of 18 942 polymorphic SNP markers and identified 41 crucial QTLs for these traits.  Three stable QTLs for TGW were identified on chromosomes 2D (QTgw-2D.3 and QTgw-2D.4) and 6A (QTgw-6A.1), with additive alleles all from the parent 8762, explaining 4.81–18.67% of the phenotypic variations.  Five stable QTLs for GNS on chromosomes 3D, 5B, 5D and 6A were identified.  QGns-5D.1 was from parent 8762, while the other four QTLs were from parent Keyi 5214, explaining 5.89–7.08% of the GNS phenotypic variations.  In addition, a stable GWS genetic locus QGws-4A.3 was detected from the parent 8762, which explained 6.08–6.14% of the phenotypic variations.  To utilize the identified QTLs, we developed STARP markers for four important QTLs, Tgw2D.3-2, Tgw2D.4-1, Tgw6A.1 and Gns3D.1.  Our results provide important basic resources and references for the identification and cloning of genes related to TGW, GNS and GWS in wheat.

Psathyrostachys huashanica Keng (2n=2x=14, NsNs) is regarded as a valuable wild relative species for common wheat cultivar improvement because of its abundant beneficial agronomic traits.  However, although the development of many wheat–P. huashanica-derived lines provides a germplasm base for the transfer of excellent traits, the lag in the identification of P. huashanica chromosomes in the wheat background has limited the study of these lines.  In this study, three novel nondenaturing fluorescence in situ hybridization (ND-FISH)-positive oligo probes were developed.  Among them, HS-TZ3 and HS-TZ4 could specifically hybridize with P. huashanica chromosomes, mainly in the telomere area, and HS-CHTZ5 could hybridize with the chromosomal centromere area.  We sequentially constructed a P. huashanica FISH karyotype and idiogram that helped identify the homologous groups of introduced P. huashanica chromosomes.  In detail, 1Ns and 2Ns had opposite signals on the short and long arms, 3Ns, 4Ns, and 7Ns had superposed two-color signals, 5Ns and 6Ns had fluorescent signals only on their short arms, and 7Ns had signals on the intercalary of the long arm.  In addition, we evaluated different ways to identify alien introgression lines by using low-density single nucleotide polymorphism (SNP) arrays and recommended the SNP homozygosity rate in each chromosome as a statistical pattern.  The 15K SNP array is widely applicable for addition, substitution, and translocation lines, and the 40K SNP array is the most accurate for recognizing transposed intervals between wheat and alien chromosomes.  Our research provided convenient methods to distinguish the homologous group of P. huashanica chromosomes in a common wheat background based on ND-FISH and SNP arrays, which is of great significance for efficiently identifying wheat–P. huashanica-derived lines and the further application of Ns chromosomes

Sesame (Sesamum indicum L.) is a significantly lucrative cash crop for millions of small-holder farmers.  Its seeds are an important source of a highly appreciated vegetable oil globally and two clinically essential antioxidant lignans, sesamin and sesamolin.  Accordingly, many countries import millions of tons of sesame seed every year.  The demand for lignan-rich sesame seeds has been increasing in recent years due to the continuous discovery of several pharmacological attributes of sesamin and sesamolin.  To meet this demand, the sesame breeder’s primary objective is to release sesame cultivars that are enriched in oil and lignans.  Thus, it is necessary to summarize the information related to the sesamin and sesamolin contents in sesame in order to promote the joint efforts of specialized research teams on this important oilseed crop.  In this article, we present the current knowledge on the sesamin and sesamolin contents in S. indicum L. with respect to the updated biosynthesis pathway, associated markers, governing loci, available variability in sesame germplasm, the in planta potential roles of these compounds in sesame, and the newly discovered pharmacological attributes.  In addition, we propose and discuss some required studies that might facilitate genomics-assisted breeding of high lignan content sesame varieties.

High-yield rice varieties with a suitable growth duration are required for mechanical transplanting in multiple cropping systems.  Daily yield is an appropriate criterion for the selection of machine-transplanted rice varieties.  The aim of this study was to investigate the growth characteristics and grain production in machine-transplanted medium indica hybrid rice with a high daily yield.  We conducted a field experiment on 20 medium indica hybrid rice varieties in 2017 and 2018.  Grain yield decreased significantly with growth duration between jointing and heading, but it increased with dry matter accumulation, growth rate between jointing and heading, dry matter partitioning to the stem plus sheath at heading, daily yield, and number of spikelets per panicle.  Compared with the medium and low daily yield variety types, the high daily yield variety type increased shoot biomass by improving crop growth rate and dry matter accumulation amount between jointing and heading and after heading.  The high daily yield variety type decreased the growth duration pre-heading and the proportions of dry matter partitioned to the leaf lamina at heading and maturity, but it also increased the post-heading accumulated dry matter in the grain and the remobilization of dry matter stored in the vegetative organs.  Furthermore, the high daily yield variety type significantly increased the occurrence rate of tillers, which is beneficial for the formation of a larger panicle size and an increase in the grain-filling rate.  These changes contributed to a 6.51–23.16% relative increase in grain yield of the high daily yield variety type.  In conclusion, the selection of high daily yield indica hybrid rice varieties with shorter pre-heading growth duration, greater tiller occurrence rate and spikelet numbers per panicle, higher post-jointing growth rates and stem plus sheath dry matter accumulation at heading is suitable for machine-transplanted rice.

Seedlessness in grape (Vitis vinifera) is an important commercial trait for both the fresh and drying markets.  However, despite numerous studies, the mechanisms and key genes regulating grape seedlessness are mostly unknown.  In this study, we sequenced the genomes of the V. vinifera seeded cultivar ‘Red Globe’, the seedless cultivar ‘Centennial Seedless’, and the derived hybrids.  Nonsynonymous single nucleotide polymorphisms (SNPs) were identified by genome sequencing and analyzed using published transcriptome data.  Nonsynonymous SNPs occurred in genes related to seed development, which were identified as protein kinases, transcription factors, and cytochrome P450s and showed differential expression during ovule development in both seeded and seedless grapes.  These nonsynonymous SNP-associated genes were mainly involved in biological processes such as hormone balance, seed coat and endosperm development, reproductive organ development, oxidation and reduction, senescence and cell death.  A potential quantitative trait locus (QTL) region associated with seed size was characterized based on the SNP-index, and expression analysis of candidate genes in the QTL region during ovule development in multiple seeded and seedless grape cultivars were conducted.  Three SNPs were further subjected to SNaPshot analysis and one SNP in G8 showed 67.5% efficiency in the grape progeny validation.  Overall, the data obtained in this study shed light on the differences in seed development between seeded and seedless progeny at the genomic level, which provides valuable resources for future functional studies and grape breeding.

To date, little attention has been paid to the effects of leaf source reduction on photosynthetic matter production, root function and post-silking N uptake characteristics at different planting densities. In a 2-year field experiment, Xianyu 335, a widely released hybrid in China, was planted at 60 000 plants ha^–1 (conventional planting density, CD) and 90 000 plants ha^–1 (high planting density, HD), respectively. Until all the filaments protruded from the ear, at which point the plants were subjected to the removal of 1/2 (T1), 1/3 (T2) and 1/4 (T3) each leaf length per plant, no leaf removal served as the control (CK). We evaluated the leaf source reduction on canopy photosynthetic matter production and N accumulation of different planting densities. Under CD, decreasing leaf source markedly decreased photosynthetic rate (P_n), effective quantum yield of photosystem II (ΦPSII) and the maximal efficiency of photosystem II photochemistry (F_v/F_m) at grain filling stage, reduced post-silking dry matter accumulation, harvest index (HI), and the yield. Compared with the CK, the 2-year average yields of T1, T2 and T3 treatments decreased by 35.4, 23.8 and 8.3%, respectively. Meanwhile, decreasing leaf source reduced the root bleeding sap intensity, the content of soluble sugar in the bleeding sap, post-silking N uptake, and N accumulation in grain. The grain N accumulation in T1, T2 and T3 decreased by 26.7, 16.5 and 12.8% compared with CK, respectively. Under HD, compared to other treatments, excising T3 markedly improved the leaf P_n, ΦPSII and F_v/F_m at late-grain filling stage, increased the post-silking dry matter accumulation, HI and the grain yield. The yield of T3 was 9.2, 35.7 and 20.1% higher than that of CK, T1 and T2 on average, respectively. The T3 treatment also increased the root bleeding sap intensity, the content of soluble sugar in the bleeding sap and post-silking N uptake and N accumulation in grain. Compared with CK, T1 and T2 treatments, the grain N accumulation in T3 increased by 13.1, 40.9 and 25.2% on average, respectively. In addition, under the same source reduction treatment, the maize yield of HD was significantly higher than that of CD. Therefore, planting density should be increased in maize production for higher grain yield. Under HD, moderate decreasing leaf source improved photosynthetic performance and increased the post-silking dry matter accumulation and HI, and thus the grain yield. In addition, the improvement of photosynthetic performance improved the root function and promoted post-silking N uptake, which led to the increase of N accumulation in grain.

This experiment was conducted to investigate the effects of selenium (Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers.  A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d.  The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg^–1.  The results showed that broilers fed the Se-supplemented diets had higher (P<0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase (GSH-Px) activities in breast and thigh muscles on d 42, and lower (P<0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde (MDA) concentration in thigh muscle on d 42 than those fed the control diet.  Broilers fed the diets supplemented with Se yeast had higher (P<0.05) pH value and lower (P<0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite.  Additionally, broilers fed the diets supplemented with 0.40 mg Se kg^–1 had lower (P<0.05) shear force in thigh muscle and higher (P<0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg^–1.  Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg^–1 had higher (P<0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg^–1, but no differences (P<0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg^–1.  The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers; and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.

This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance, rumen function and plasma lipopolysaccharides (LPS) content and immunity parameters of beef cattle.  Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment.  The dietary treatments were: control diet (CTR), CTR supplemented with 1 g live yeast (2×10¹⁰ live cell g^–1 per cattle per day (YST1), CTR supplemented with 2 g live yeast per cattle per day (YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides (30.0%≤β-glucan≤35.0%, and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day (YCW).  The average daily gain was higher (P=0.023) and feed conversion ratio was lower (P=0.042) for the YST2 than the CTR.  The digestibility of neutral detergent fiber (P=0.039) and acid detergent fiber (P=0.016) were higher in yeast supplemented groups.  The acetic acid:propionic acid of the YST2 was lower compared with the CTR (P=0.033).  Plasma LPS (P=0.032), acute phase protein haptoglobin (P=0.033), plasma amyloid A (P=0.015) and histamine (P=0.038) were lower in the YST2 compared with the CTR.  The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85, Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher (P<0.001), while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower (P<0.001) compared with the CTR.  Little differences were observed between the CTR, YST1 and YCW in growth performance, ruminal fermentation characteristics, microbial populations, immunity indices and total tract nutrient digestibility.  It is concluded that the YST2 could promote fibrolytic microbial populations, decrease starch-utilizing bacteria, reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters, which can lead to an improvement in growth performance in beef cattle.