Effect of Preplant Fertilizer on Agronomic and Physiological Traits of Soybean Cultivars from Different Breeding Programs

Understanding the changes in agronomic and physiological traits associated with yield genetic gain is important for soybean production and future breeding strategy. The objective of this study was to compare the older and modern cultivars to learn whether the yield improvements depend on preplant fertilizer or the plant productivity improvement, A set of older cultivars, with their modern counterparts derived from breeding programs in Liaoning and Ohio were evaluated for their agronomic and physiological traits under different fertilizer levels from 2004 to 2006. There was no improvement of response to N and P preplant fertilizer for genotypes. After more than 70 yr breeding, soybean breeders made some improvements in agronomic and physiological traits that contribute to yield increase. When compared to older cultivar, modern Liaoning and Ohio cultivars were shorter and more resistance to lodging, had greater leaf density, higher harvest index, more leaf area per plant, and greater photosynthetic rate, transpiration rate and stomatal conductance at the beginning of seed development. Ohio cultivars were more resistant to lodging as if selected for easy harvest by combine, even under high N and P preplant fertilizer level, which resulted in Ohio cultivars with higher and stable yield productivity.

Effectivity of arbuscular mycorrhizal fungi collected from reclaimed mine soil and tallgrass prairie

We examined suitability of arbuscular mycorrhizal fungi (AMF) associated with cool-season nonnative forages on reclaimed surface-mined land in southeast Ohio for establishment of native warm-season grasses. The goal of establishing these grasses is to diversify a post-reclamation landscape that is incapable of supporting native forest species. A 16-week glasshouse study compared AMF from a 30-year reclaimed mine soil (WL) with AMF from native Ohio tallgrass prairie soil (CL). Four native grasses were examined from seedling through 16 weeks of growth. Comparisons were made between CL and WL AMF on colonized (+AMF) and non-colonized plants (–AMF) at three levels of soil phosphorus (P). Leaves were counted at 4 week intervals. Shoot and root biomass and percent AMF root colonization were measured at termination. We found no difference between WL and CL AMF. Added soil P did not reduce AMF colonization, but did reduce AMF efficacy. Big bluestem (Andropogon gerardii Vitman), Indiangrass (Sorghastrum nutans (L.) Nash), and tall dropseed (Sporobolus asper (Michx.) Kunth) benefited from AMF only at low soil P while slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners) exhibited no benefit. Establishment of tallgrass prairie dominants big blue-stem and Indiangrass would be supported by the mine soil AMF. It appears that the non-native forage species have supported AMF equally functional as AMF from a regionally native tallgrass prairie. Tall dropseed and slender wheatgrass were found to be less dependent on AMF than big bluestem or Indiangrass and thus would be useful in areas with little or no AMF inoculum.

Soil compaction and arbuscular mycorrhizae affect seedling growth of three grasses

Soil compaction is a limitation to establishment of native forest species on reclaimed surfacemined lands in Appalachia. Previously, non-native forage species such as tall fescue (Schedonorus arundinaceus(Schreb.) Dumort., nom. cons.) have been planted because they easily established on reclaimed mine soil. There is now interest in establishing robust native prairie species to enhance biodiversity and provide greater potential for root activity in the compacted soil. We conducted a 10-week glasshouse study comparing growth of “Pete” eastern gamagrass (Tripsacum dactyloidesL.), “Bison” big bluestem (Andropogon gerardiiVitman), and “Jesup MaxQ” tall fescue at soil bulk densities (BD) of 1.0, 1.3, and 1.5 g·cm-3. We also examined effects of arbuscular-mycorrhizal fungi (AMF) on plant growthin relation to compaction. Sources of AMF were a reclaimed surface coal mine soil and a native tallgrass prairie soil. Shoot and root biomass of tall fescue and big bluestem were reduced at 1.5 BD while eastern gamagrass growth was not affected. Growth ofbig bluestem and eastern gamagrass was greaterwith AMF than without, butsimilar between AMF sources. Tall fescue growthwas not enhanced by AMF. Overall, tall fescue biomass was 3 times greater than eastern gamagrass and 6 times greater than big bluestem when comparing only AMF-colonized grasses. Eastern gamagrass and big bluestem are both slower to establish than tall fescue. Eastern gamagrass appears to be more tolerant of compaction, while big bluestem appears somewhat less tolerant.

Genotyping-by-sequencing of Brassica oleracea vegetables reveals unique phylogenetic patterns, population structure and domestication footprints

Brassica oleracea forms a diverse and economically significant crop group.Improvement efforts are often hindered by limited knowledge of diversity contained within available germplasm.Here,we employ genotyping-by-sequencing to investigate a diverse panel of 85 landrace and improved B.oleracea broccoli,cauliflower,and Chinese kale entries.Ultimately,21,680 high-quality SNPs were used to reveal a complex and admixed population structure and clarify phylogenetic relationships among B.oleracea groups.Each broccoli landrace contained,on average,8.4 times as many unique alleles as an improved broccoli and landraces collectively represented 81%of all broccoli-specific alleles.Commercial broccoli hybrids were largely represented by a single subpopulation identified within a complex population structure.Greater allelic diversity in landrace broccoli and 96.1%of SNPs differentiating improved cauliflower from landrace cauliflower were common to the larger pool of broccoli germplasm,supporting a parallel or later development of cauliflower due to introgression events from broccoli.Chinese kale was readily distinguished by principal coordinate analysis.Genotyping was accomplished with and without reliance upon a reference genome producing 141,317 and 20,815 filtered SNPs,respectively,supporting robust SNP discovery methods in neglected or unimproved crop groups that lack a reference genome.This work clarifies the population structure,phylogeny,and domestication footprints of landrace and improved B.oleracea broccoli using many genotyping-by-sequencing markers.Additionally,a large pool of genetic diversity contained in broccoli landraces is described which may enhance future breeding efforts.

Identification of QTLs for berry acid and tannin in a Vitis aestivalisderived‘Norton'-based population

Acidity and tannins are among the grape berry quality traits that influence wine quality.Despite advantageous environmental tolerances of Vitis aestivalis-derived‘Norton',its acidity and tannin concentrations often deviate from expectations set for V.vinifera.Identification of the genetic determinants of malic acid,tartaric acid,pH,and tannin can assist in the improvement of new hybrid cultivars.For this purpose,a‘Norton'and V.vinifera‘Cabernet Sauvignon'hybrid population containing 223 individuals was used to construct a linkage map containing 384 simple sequence repeat(SSR)and 2,084 genotyping-by-sequencing(GBS)-derived single nucleotide polymorphism(SNP)markers.The resulting map was 1,441.9 cM in length with an average inter-marker distance of 0.75 cM and spanned 19 linkage groups(LGs).Quantitative trait loci(QTLs)were detected for malic acid,tartaric acid,pH,and tannin.QTLs for malic acid(LG 8)and pH(LG 6)were observed across multiple years and explained approximately 17.7%and 18.5%of the phenotypic variation,respectively.Additionally,QTLs for tartaric acid were identified on linkage groups 1,6,7,9,and 17 and tannin on LG 2 in single-year data.The QTLs for tartaric acid explained between 8.8−14.3%and tannin explained 24.7%of the phenotypic variation.The markers linked to these QTLs can be used to improve hybrid cultivar breeding through marker-assisted selection.

Transcriptomic analysis of grapevine in response to ABA application reveals its diverse regulations during cold acclimation and deacclimation

Abscisic acid(ABA)plays crucial regulatory roles in cold acclimation and deacclimation of grapevine,making it a potential tool to be utilized in vineyards for the acquisition of preferred phenotypes in winter and spring.To understand the function of ABA,we conducted experiments during cold acclimation and deacclimation and evaluated the impact of exogenous ABA on the grapevine transcriptome.RNA-seq data were collected periodically hours or days after ABA treatment.Transcriptomic data were analyzed using principal component analysis(PCA),hierarchical clustering,unsupervised weighed gene co-expression network analysis(WGCNA),contrast-based differentially expressed genes(DEGs)identification and pre-ranked gene set enrichment analysis(GSEA).Our results suggest that ABA functions differently during cold acclimation and deacclimation by selectively regulating key pathways including auxin/indole acetic acid(IAA)metabolism,galactose metabolism and ribosome biogenesis.We also identified the activation of several apparent negative feedback systems that regulated ABA-induced transcriptomic changes,suggesting the existence of a balancing system in response to excessive ABA.This balancing systems potentially eliminates the long-term negative effect on grapevine growing from using ABA in the field.These findings advance our understanding about the regulation of grapevine physiology during dormancy and supports the potential of applying ABA as a cultural practice to mitigate cold injury in winter and spring.

大豆骨干品系在特定育种程序中的作用

来源于遗传多样性的变异将有助于提高育种效率,通过血缘关系分析可以了解后代群体的遗传结构。研究的目的是评估美国俄亥俄州立大学大豆育种程序中对产量改良起过重大贡献的骨干品系的作用。在俄亥俄州立大学大豆育种程序中,通常采用自己创造的骨干育种材料或来自其他育种程序的优异品种(系)做亲本进行常年杂交组配,这样带来了骨干血缘年度间的差异性,骨干品种(系)做亲本的使用年限也是有限的,然而,由于本育种程序中缺乏做豆腐用的骨干亲本,使Ohio FG1品种用作亲本的年限延长。Kottman,A98-980047,U97-3114,HS 98-3628,HS 94-4533,Athow和HS 93-4118等7个骨干品种(系)对俄亥俄州立大学大豆产量改良起主要作用。后代群体中含50%以上骨干血缘品系的平均产量和所有被鉴定品系的平均产量呈极显著正相关,相关系数为0.9146,含50%以上骨干血缘品系的平均产量越高,所有被鉴定品系的平均产量也越高。但后代群体中骨干品系的血缘百分率和所有被鉴定品系的平均产量间不存在线性关系,说明在选择骨干品系做亲本时,除了考虑骨干品系的数量外,还要考虑骨干品系的配合力。俄亥俄州立大学大豆育种程序中,26个骨干品系衍生的后代中有11个的衍生后代平均产量超过对照品种,而且,这11个骨干品系中又有7个来自俄亥俄州立大学大豆育种程序,说明育种中间材料在产量改良中起着关键性作用。血缘分析结果表明,7个骨干品系来源于Williams、Essex、Amsoy、Wayne、Cor-soy 5个老品种和一个现代品系A86-301024。1998至2008年俄亥俄州立大学育成的19个油用品种和8个豆腐用品种中分别有17和14个亲本来自育种程序本身,进一步说明骨干品系的创造在品种选育中起着重大作用。

中国辽宁和美国俄亥俄新老大豆品种的比较研究(英文)

未来的大豆产量获得将取决于对过去遗传改良的认识。在中国辽宁省和美国俄亥俄州布置试验比较研究2个地区育成的新老大豆品种,以了解这2个地区大豆遗传改良的一些进展。结果表明:在俄亥俄试验点,俄亥俄州立大学育成的新品种比老品种增产78%,比辽宁新品种增产22%。在辽宁省试验点,俄亥俄新品种和辽宁新品种均比老品种增产约50%。在辽宁试验环境下,大豆植株生长较高大,倒伏也相对严重,尤其老品种倒伏更重。与辽宁新品种和老品种相比,俄亥俄新品种蛋白质含量较低,脂肪含量较高。两地的育种家对大豆的产量遗传改良成绩显著,同时植株得到矮化、节间缩短和抗倒伏能力提高,主茎籽粒产量比例提高、粒/茎比增加。辽宁育种家注重籽粒大小和蛋白含量的改良,但这2个性状没有引起俄亥俄育种家的重视,双方互换种质将有利于大豆的遗传改良。

Compartmentalized Metabolic Engineering for Artemisinin Biosynthesis and Effective Malaria Treatment by Oral Delivery of Plant Cells

Artemisinin is highly effective against drug-resistant malarial parasites, which affects nearly half of the global population and kills 〉500 000 people each year. The primary cost of artemisinin is the very expensive process used to extract and purify the drug from Artemisia annua. Elimination of this apparently unnecessary step will make this potent antimalarial drug affordable to the global population living in endemic regions. Here we reported the oral delivery of a non-protein drug artemisinin biosynthesized （~0.8 mg/g dry weight） at clinically meaningful levels in tobacco by engineering two metabolic pathways targeted to three different cellular compartments （chloroplast, nucleus, and mitochondria）. The doubly transgenic lines showed a three-fold enhancement of isopentenyl pyrophosphate, and targeting AACPR, DBR2, and CYP71AV1 to chloroplasts resulted in higher expression and an efficient photo-oxidation of di- hydroartemisinic acid to artemisinin. Partially purified extracts from the leaves of transgenic tobacco plants inhibited in vitro growth progression of Plasmodium falciparum-infected red blood cells. Oral feeding of whole intact plant cells bioencapsulating the artemisinin reduced the parasitemia levels in challenged mice in comparison with commercial drug. Such novel synergistic approaches should facilitate low-cost production and delivery of artemisinin and other drugs through metabolic engineering of edible plants.

The Arabidopsis bZIP1 Transcription Factor Is Involved in Sugar Signaling, Protein Networking, and DNA Binding

Sugar signaling is a mechanism that plants use to integrate various internal and external cues to achieve nutrient homeostasis, mediate developmental programs, and articulate stress responses. Many bZlP transcription factors are known to be involved in nutrient and/or stress signaling. An Arabidopsis Sl-group bZlP gene, AtbZIP1, was identified as a sugar-sensitive gene in a previous gene expression profiling study （Plant Cell. 16, 2128-2150）. In this report, we show that the expression of AtbZIP1 is repressed by sugars in a fast, sensitive, and reversible way. The sugar repression of Atb- ZIP1 is affected by a conserved sugar signaling component, hexokinase. Besides being a sugar-regulated gene, AtbZIP1 can mediate sugar signaling and affect gene expression, plant growth, and development. When carbon nutrients are limited, gain or loss of function of AtbZlP1 causes changes in the rates of early seedling establishment. Results of phenotypic analyses indicate that AtbZlP1 acts as a negative regulator of early seedling growth. Using gain- and loss-of-function plants in a microarray analysis, two sets of putative AtbZIP1-regulated genes have been identified. Among them, sugar-responsive genes are highly over-represented, implicating a role of AtbZlP1 in sugar-mediated gene expression. Using yeast two-hybrid （Y-2-H） screens and bimolecular fluorescence complementation （BiFC） analyses, we are able to recapitulate extensive C/S1 AtbZlP protein interacting network in living cells. Finally, we show that AtbZIP1 can bind ACGT-based motifs in vitro and that the binding characteristics appear to be affected by the heterodimerization between AtbZlP1 and the C-group AtbZIPs, including AtbZlP10 and AtbZlP63.

Seven Things We Think We Know about Auxin Transport

Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.

Redox sensor QSOX1 regulates plant immunity by targeting GSNOR to modulate ROS generation

Reactive oxygen signaling regulates numerous biological processes,including stress responses in plants.Redox sensors transduce reactive oxygen signals into cellular responses.Here,we present biochemical evidence that a plant quiescin sulfhydryl oxidase homolog(QSOX1)is a redox sensor that negatively regulates plant immunity against a bacterial pathogen.The expression level of QSOX1 is inversely correlated with pathogen-induced reactive oxygen species(ROS)accumulation.Interestingly,QSOX1 both senses and regulates ROS levels by interactingn with and mediating redox regulation of S-nitrosoglutathione reductase,which,consistent with previous findings,influences reactive nitrogen-mediated regulation of ROS generation.Collectively,our data indicate that QSOX1 is a redox sensorthat negatively regulates plant immunity by linking reactive oxygen and reactive nitrogen signaling to limit ROS production.