Physiological and Biochemical Characteristics and Response Patterns of Salinity Stress Responsive Genes (SSRGs) in Wild Quinoa (<i>Chenopodium quinoa</i> L.)

Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils. Quinoa, a protein-comprehensive cereal in the plant kingdom, is an exceptional crop in terms of salt stress tolerance level. It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms. In this study, the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution. The physiological, biochemical characteristics and agronomic traits were investigated, and the response patterns of three salt stress-responsive genes (SSRGs) in quinoa were determined by real-time PCR. The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl. Salt stress significantly induced expression of superoxide dismutase (SOD), peroxidase (POD), and particularly betaine aldehyde dehydrogenase (BADH). BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings, particularly at high NaCl concentrations, as it displayed upregulation until 24 h under 100 mM salt treatment. Moreover, it showed upregulation until 12 h under 250 mM salt stress. Taken together, these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa. Based on the expression level and prompt response induced by NaCl, we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development. Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth. Therefore, an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm, which is useful to the utilization of saline soils. Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.     

转录组和代谢组分析瘤菌根菌对铁皮石斛的促生机制

为筛选出促进铁皮石斛(Dendrobium officinale)生长的差异表达基因和差异代谢物,对瘤菌根菌与无菌盆栽铁皮石斛苗共生后形成的侧根根系进行转录组、代谢组和双组学联合分析。结果表明,转录组分析共找到262条差异表达基因富集到了35条通路中,其中内质网蛋白质加工通路途径的差异基因最多,其次为氨基糖和核苷酸糖代谢通路。代谢组分析共检测出194个差异代谢物富集到33个KEGG通路中,其中代谢途径的差异代谢物最多有133个,其次为不同环境的微生物代谢途径的差异代谢物有70个。通过联合分析,有9个差异基因的差异表达导致丝氨酸、谷氨酸、D-甘露糖和激素等代谢物的积累量发生变化,这可能是瘤菌根菌促进铁皮石斛生长的重要原因。因此,推测瘤菌根菌促进铁皮石斛生长与氨基酸、糖、植物激素的积累及相关基因的表达变化有关。     

光质对白芨组培苗生理特性及酶基因表达的影响

为探讨光质对白芨(Bletilla striata)组培苗生长发育的影响,对不同光质下白芨组培苗的生长特征、抗氧化酶活性以及酶基因表达进行了研究。结果表明,蓝光和红光对白芨生长有显著促进作用,绿光的作用不明显。除了CAT外,不同光质处理白芨的APX、POD、SOD活性均呈上升趋势,且黄光处理的白芨SOD和APX活性最高,红光处理的POD活性最高,绿光处理的抗氧化酶活性比其他光质的低,蓝光处理35~45 d对抗氧化酶基因表达具有促进作用。因此,红光和黄光促进白芨生根组培苗的长高和生根;不同光质处理总体上提高了白芨氧化酶活性;白芨抗氧化酶基因的表达在蓝光处理下最大。     

藜麦营养学、生态学及种质资源学研究进展

藜麦Chenopodium quinoa (2n=4x=36)属于石竹目藜属,起源于南美洲安第斯山区,在该地区有几千年的栽培历史。近年来,因其营养的全面性和广泛的生态适应性引起世界范围的关注,开始了从印第安主粮到一种战略资源的蜕变之路。本文综述近年来藜麦的营养学、生态学和种质资源学研究进展与亟待解决的问题,并对藜麦的应用前景以及供求现状提出对策和展望。     

藜麦功能成分综合研究与利用

藜麦(Chenopodium quinoa Willd)为藜科藜属一年生草本植物,因独特的营养价值和潜在的保健功能引起研究者们的关注。概述了藜麦的生长发育、营养价值、功能成分、基因分析及其生理功能的研究进展。针对国内外藜麦功能成分综合研究利用进展,提出藜麦的种质创新、食品保健、医药研发及其新型功能食品研制与产业化对策,对藜麦产业、食品保健和医药研发等领域具有重要的参考价值。     

Regulation of Ethylene Biosynthesis Under Salt Stress in Red Pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) by 1-Aminocyclopropane-1-Carboxylic Acid (ACC) Deaminase-producing Halotolerant Bacteria

The present study was carried out to understand the mechanism of salt stress amelioration in red pepper plants by inoculation of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing halotolerant bacteria. In general, ethylene production, ACC concentration, ACC synthase (ACS), and ACC oxidase (ACO) enzyme activities increased with increasing levels of salt stress. Treatment with halotolerant bacteria reduced ethylene production by 47–64%, ACC concentration by 47–55% and ACO activity by 18–19% in salt-stressed (150 mmol NaCl) red pepper seedlings compared to uninoculated controls. ACS activity was lower in red pepper seedlings treated with Bacillus aryabhattai RS341 but higher in seedlings treated with Brevibacterium epidermidis RS15 (44%) and Micrococcus yunnanensis RS222 (23%) under salt-stressed conditions as compared to uninoculated controls. A significant increase was recorded in red pepper plant growth under salt stress when treated with ACC deaminase-producing halotolerant bacteria as compared to uninoculated controls. The results of this study collectively suggest that salt stress enhanced ethylene production by increasing enzyme activities of the ethylene biosynthetic pathway. Inoculation with ACC deaminase-producing halotolerant bacteria plays an important role in ethylene metabolism, particularly by reducing the ACC concentration, although a direct effect on reducing ACO activity was also observed. It is suggested that growth promotion in inoculated red pepper plants under inhibitory levels of salt stress is due to ACC deaminase activity present in the halotolerant bacteria.     

60份国内外藜麦材料子粒的品质性状分析

研究藜麦子粒的品质性状,可以为藜麦育种、加工及消费提供参考。本研究对4份国内和56份国外藜麦材料子粒的品质性状进行了分析,结果表明60份藜麦材料子粒的千粒重、灰分、蛋白质、淀粉、脂肪、粗纤维、总黄酮和总多酚平均含量分别为4.23 g、2.28%、14.03%、57.71%、6.53%、2.46%、1.83 mg/g和1.49 mg/g。国内藜麦材料的灰分、蛋白质和总多酚平均含量较高,分别为3.47%、14.92%和1.78 mg/g;秘鲁藜麦材料的脂肪、粗纤维和总黄酮平均含量较高,分别为6.69%、2.66%和2.03 mg/g;美国藜麦材料的淀粉平均含量较高,为59.91%;玻利维亚藜麦材料的千粒重较高,为4.32 g;不同子粒颜色藜麦材料之间的品质存在差异,黑色藜麦材料的蛋白质含量较高,白色和红色藜麦材料的淀粉含量较高,红色和黑色藜麦材料的粗纤维、总黄酮和总多酚含量较高。     

Phenological growth stages of quinoa (Chenopodium quinoa) based on the BBCH scale

Quinoa (Chenopodium quinoa) is a pseudocereal native from the Andean region of South America that has increased in importance worldwide. Quinoa is now considered an alternative to traditional crops in a climate change scenario, considering its ability to adapt to marginal soils, droughts and frosts. Despite the interesting agronomic and nutritional features of this crop, research into quinoa is characterised by individual attempts to define its phenological stages without an international consensus. A unique criterion to quantify the phenology of quinoa could become a useful tool for researchers and plant breeders in future work by standardising this information for international cooperation. In this article, a proposed scale of the phenological growth stages of quinoa based on the BBCH coding system (Biologische Bundesanstalt Bundessortenamt und CHemische Industrie) was developed. Growth stages were described utilising the decimal code of the BBCH system, and figures were included for the most representative stages.     

Phytochemical and genetic characterization of five quinoa (<Emphasis Type="Italic">Chenopodium quinoa</Emphasis> Willd.) genotypes introduced to Egypt

Due to its substantial nutritional value, quinoa (Chenopodium quinoa Willd.) is currently attracting worldwide attention. Quinoa is characterized by a high adaptability to various environmental conditions. This is the first report on the phytochemical and genetic evaluation of quinoa germplasms introduced to Egypt, and the results could be used to implement propagation techniques in the future. For phytochemical characterization, 41 traits, including primary and secondary metabolites, antioxidant molecules, sugars, organic acids and fatty acids, were evaluated. At the same time, 4 RAPD and 7 ISSR markers were used for genetic analysis. UPGMA analysis of RAPD and ISSR polymorphic markers, their combined dataset and phytochemical traits were used to evaluate genetic relationships among genotypes. The quinoa genotypes displayed reasonable variation in the studied phytochemical traits. The results of the genetic analysis confirmed that RAPD and ISSR markers could be used to distinguish effectively quinoa genotypes. The phytochemical and genetic characterization reported herein will be a promising guide for breeding seed quality in quinoa.     

Effects of 28-homobrassinolide on growth, lipid peroxidation and antioxidative enzyme activities in seedlings of Zea mays L. under salinity stress

The effects of 28-homobrassinolide (28-homoBL) on seedling growth, lipid peroxidation and antioxidative enzyme activities in the seedlings of Zea mays L. (var. Partap-1) under salt (NaCl) stress were studied. The surface-sterilized seeds were germinated in petriplates containing different concentrations of NaCl (25, 50, 75 and 100 mM) only, 28-homoBL (10⁻⁷, 10⁻⁹ and 10⁻¹¹ M) only and NaCl supplemented with 28-homoBL for 7 days. The activities of superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (POD, EC 1.11.1.7), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APOX, EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2) were analysed in 7 day-old seedlings. It was observed that 28-homoBL treatments reduced the toxicity of salt on seedling growth considerably. Lipid peroxidation level was significantly increased under saline stress, but lowered with 28-homoBL applications revealing less oxidative damage. Further 28-homoBL treatments to the seedlings showed an enhancement in activities of SOD, POD, CAT and APOX. The activities of all antioxidative enzymes were further increased in seedlings treated with solution containing 28-homoBL and salt together as compared to seedlings treated with different concentration of salt solution only.     

Impact of heat and drought stress on peroxisome proliferation in quinoa

Although peroxisomes play a key role in plant metabolism under both normal and stressful growth conditions, the impact of drought and heat stress on the peroxisomes remains unknown. Quinoa represents an informative system for dissecting the impact of abiotic stress on peroxisome proliferation because it is adapted to marginal environments. Here we determined the correlation of peroxisome abundance with physiological responses and yield under heat, drought and heat plus drought stresses in eight genotypes of quinoa. We found that all stresses caused a reduction in stomatal conductance and yield. Furthermore, H₂O₂ content increased under drought and heat plus drought. Principal component analysis demonstrated that peroxisome abundance correlated positively with H₂O₂ content in leaves and correlated negatively with yield. Pearson correlation coefficient for yield and peroxisome abundance (r = ?0.59) was higher than for commonly used photosynthetic efficiency (r = 0.23), but comparable to those for classical stress indicators such as soil moisture content (r = 0.51) or stomatal conductance (r = 0.62). Our work established peroxisome abundance as a cellular sensor for measuring responses to heat and drought stress in the genetically diverse populations. As heat waves threaten agricultural productivity in arid climates, our findings will facilitate identification of genetic markers for improving yield of crops under extreme weather patterns.     

Differences in the success of sugar maple and red maple seedlings on acid soils are influenced by nutrient dynamics and light environment

Variation in tolerance to nutrient limitations may contribute to the differential success of sugar maple ( Acer saccharum Marsh.) and red maple ( Acer rubrum L.) on acid soils. The objectives of this study were to examine these relationships as influenced by light environment and test whether sensitivity to nutrient stress is mediated by oxidative stress. First-year sugar maple and red seedlings were grown on forest soil cores contrasting in nutrient availability under high or low light intensity. Foliar nutrition, photosynthesis, growth and antioxidant enzyme activity were assessed. Photosynthesis and growth of sugar maple were significantly lower on nutrient-poor soils and were correlated with leaf nutrient status with Ca and P having the strongest influence. For red maple, only chlorophyll content showed sensitivity to the nutrient-poor soils. High light exacerbated the negative effects of nutrient imbalances on photosynthesis and growth in sugar maple. Antioxidant enzyme activity in sugar maple was highest in seedlings growing on nutrient-poor soils and was inversely correlated with photosynthesis, Ca, P, and Mg concentrations. These results suggest that: (1) sugar maple is more sensitive to nutrient stresses associated with low pH soils than red maple; (2) high light increases sugar maple sensitivity to nutrient stress; (3) the negative effects of nutrient imbalances on sugar maple may be mediated by oxidative stress.     

Effect of low light intensity on growth and accumulation of secondary metabolites in roots of Glycyrrhiza uralensis Fisch

Effects of low light intensity on growth and accumulation of secondary metabolites of a medicinal plant Glycyrrhiza uralensis Fisch. were investigated. Hydroponic-cultivated one year-old rhizome seedlings were grown under three low irradiances, 200, 100, and 50 μmol m⁻² s⁻¹ for 135 days. Control plants were cultured under natural light conditions. Low light intensity stress decreased leaf thickness, photosynthesis and biomass, but increased leaf area and chlorophyll concentrations. Low light intensity also significantly increased accumulation of glycyrrhizic acid and liquiritin in the root, while the maximum values of both secondary metabolites were obtained under an irradiance of 100 μmol m⁻² s⁻¹. Concentrations of both secondary metabolites were negatively correlated with root biomass. The results suggested that G. uralensis could endure an environment with low light intensity and suitable light control might increase the secondary metabolite contents within agroforestry systems.     

外源色氨酸对油菜幼苗色氨酸下游代谢网络及生长发育的影响

色氨酸是合成蛋白质的重要氨基酸,也是植物生长激素IAA和某些次生代谢产物的前体物质,对植物生长发育及病虫害防御有重要作用。为了探究色氨酸对白菜型油菜(Brassica rapa L)生长发育及防御物质累积的影响及其可能的机制,该研究采用外源色氨酸对油菜幼苗进行叶面喷施,分析了色氨酸对油菜幼苗生长发育及生长素IAA和次生代谢产物芥子油苷合成的影响。结果表明：(1)低浓度色氨酸(100 mg/L)处理可有效地促进油菜叶片与根系的发育,但随着浓度增高,促进作用逐渐减弱。(2)荧光定量PCR分析表明,外源色氨酸处理后,油菜幼苗叶片中生长素IAA的3条合成途径都被激活,IPA途径的BrTAA1和BrYUCCA8、IAM途径的BrAMI1及IAOx途径的BrCYP71A13和BrNIT2等关键酶基因的表达均受到强烈的诱导,因而导致IAA的含量显著提高。(3)外源色氨酸处理还激活了下游的吲哚族芥子油苷的合成途径调控因子基因BrMYB34、BrMYB51和BrMYB122以及合成酶基因BrCYP79B2、BrCYP79B3、BrCYP83B1、BrSUR1的表达,同时抑制了其降解酶基因BrTGG1、BrPEN2的表达,从而引起吲哚族芥子油苷的累积。研究发现,外源色氨酸处理可通过调控生长素IAA合成途径和吲哚族芥子油苷的合成途径相关基因表达,有效地促进油菜生长调节物质和生物防御物质的累积,从而增加生物量和提高潜在抗病能力。     

Satellite DNA landscapes after allotetraploidization of quinoa (Chenopodium quinoa) reveal unique A and B subgenomes

If two related plant species hybridize, their genomes may be combined and duplicated within a single nucleus, thereby forming an allotetraploid. How the emerging plant balances two co‐evolved genomes is still a matter of ongoing research. Here, we focus on satellite DNA (satDNA), the fastest turn‐over sequence class in eukaryotes, aiming to trace its emergence, amplification, and loss during plant speciation and allopolyploidization. As a model, we used Chenopodium quinoa Willd. (quinoa), an allopolyploid crop with 2n = 4x = 36 chromosomes. Quinoa originated by hybridization of an unknown female American Chenopodium diploid (AA genome) with an unknown male Old World diploid species (BB genome), dating back 3.3–6.3 million years. Applying short read clustering to quinoa (AABB), C. pallidicaule (AA), and C. suecicum (BB) whole genome shotgun sequences, we classified their repetitive fractions, and identified and characterized seven satDNA families, together with the 5S rDNA model repeat. We show unequal satDNA amplification (two families) and exclusive occurrence (four families) in the AA and BB diploids by read mapping as well as Southern, genomic, and fluorescent in situ hybridization. Whereas the satDNA distributions support C. suecicum as possible parental species, we were able to exclude C. pallidicaule as progenitor due to unique repeat profiles. Using quinoa long reads and scaffolds, we detected only limited evidence of intergenomic homogenization of satDNA after allopolyploidization, but were able to exclude dispersal of 5S rRNA genes between subgenomes. Our results exemplify the complex route of tandem repeat evolution through Chenopodium speciation and allopolyploidization, and may provide sequence targets for the identification of quinoa's progenitors.