Genetics of desynaptic mutants in pearl millet

Summary Two desynaptic mutants, one of spontaneous origin and the other induced through colchicine treatment, were obtained in pearl millet. The desynpatic character was a monogenically controlled recessive one. Tests for allelism have indicated that the desynaptic genes of the two sources were allelic. Both complete and medium-strong desynaptic plants followed a monogenic pattern of inheritance and were found to be allelic. Medium-strong desynpatic plants on selfing produced both complete and medium-strong desynaptics in approximately equal numbers. It is suggested that the differential expression of the desynaptic character might be due to the presence of modifying genes.     

Variation in levels of lipid components and protein in ecogeographic races of Sorghum bicolor

Sorghum bicolor (L.) Moench is a widespread grass of the African savanna. It contains wild and cultivated subspecies which have morphologically distinct ecogeographic races. Measurements of the amount of oil and protein in sorghum grains revealed significant differences in protein levels between wild and cultivated subspecies. Measurements of the relative percentages of fatty acid components of oil also revealed significant differences in levels of oleic and linoleic acid among wild and cultivated races. We conclude that morphological differences acquired in the course of differentiation of ecogeographic races have been paralleled by differentiation in levels of lipid components and grain protein levels.     

不同覆盖方式对黄土高原旱地土壤水分及糜子生长、光合特性和产量的影响

为探索黄土高原旱地覆盖栽培模式下糜子田土壤蓄水保墒和节水增产效果,于2011—2013年连续3个糜子生长季在陕西横山县小杂粮试验示范基地,研究了不同覆盖栽培方式对农田土壤水分、糜子生长发育、光合特性、产量及水分利用效率的影响.试验设置4种覆盖栽培处理,分别是“W”垄覆地膜+垄间覆秸秆(SG)、垄覆地膜+垄间覆秸秆(LM)、双垄面覆地膜+垄间覆秸秆(QM)、秸秆覆盖(JG)处理,以传统平作无覆盖(CK)为对照.结果表明：各覆盖处理均较CK显著提高了糜子各生育期0～100 cm土层土壤含水量,其中以SG处理蓄水保墒效果最好,其次依次为LM、QM和JG处理,且各覆盖处理间差异达到显著水平.在各覆盖处理中,SG处理对糜子生长发育和光合能力的影响最大,增产效果最显著,3年平均产量和水分利用效率分别较CK提高55.9％和64.9％,其中各覆盖处理之间差异达到显著水平.因此,“W”垄覆地膜垄间覆秸秆的二元沟垄集雨覆盖种植模式提高糜子产量和水分利用效率的效果最为明显,适宜在黄土高原旱地糜子生产中应用和推广.     

Stable isotope evidence for the consumption of millet and other plants in Bronze Age Italy

Stable carbon and nitrogen isotope analysis was carried out on human and animal bones from four inland Early and Middle Bronze Age sites in Northern and Southern Italy. The main aims of the investigation were to explore the contribution of plant foods to the human diet and to examine any dietary differences between and within each of the sites. At two of the sites in Northern Italy, human and animal bones were significantly enriched in ¹³C. This finding was attributed to the consumption of domestic millets (Panicum miliaceum and/or Setaria italica), which are C₄ pathway plants. Conversely, individuals from the two Bronze Age sites in Southern Italy were significantly depleted in ¹³C compared to those from the north. Here, millet was absent from the diet, and protein from C₃ plants made a much greater dietary contribution than animal protein. This finding highlights the importance of cereal cultivation, most likely of wheat and barley, in the south of Italy during the Bronze Age. Overall, our results support the idea that the widespread cultivation of millet first occurred in Northern Italy, following its introduction from across the Alps in Central Europe. Finally, we found no significant differences in the stable isotope values between individuals at each site, when grouped by their sex or presence of grave goods. This leads to the conclusion that any status difference that may have existed is not reflected in the long‐term dietary record, or at least not as measurable by stable isotope analysis. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Host-specific Variation in Infection by Toxigenic Fungi and Contamination by Mycotoxins in Pearl Millet and Corn

Pearl millet is widely consumed in regions of Africa and Asia, and is increasingly being grown as an alternative grain in drought-prone regions of the United States. Pearl millet and corn were grown in dryland conditions at Tifton, Georgia, USA and grains were compared for pre-harvest infection by potentially toxigenic fungi and contamination by mycotoxins. Corn hybrids Agripro 9909 and Pioneer 3146, and pearl millet Tifgrain 102 were grown in 2000 and 2001; pearl millet HGM 100 was included in the test in 2001. Hybrids were sown on multiple planting dates in each year to induce variation in flowering time. Host species differed in the frequency of isolation of potentially toxigenic fungal species in both years. Across years, corn hybrids were more prone to infection by Aspergillus flavus Link (maximum isolation frequency = 8.8%) and Fusarium moniliforme Sheldon sensu lato (maximum isolation frequency = 72.8%), with corresponding greater concentrations of aflatoxins (maximum concentration = 204.9 μg kg⁻¹) and fumonisins (maximum concentration = 34,039 μg kg⁻¹). Pearl millet was more prone to infection by F. semitectum Berk. & Ravenel (maximum isolation = 74.2%) and F. chlamydosporum Wollenweb & Reinking (maximum isolation = 33.0%), and contamination by moniliformin (maximum contamination = 92.1 μg kg⁻¹). Beauvericin (maximum concentration = 414.6 μg kg⁻¹) was present in both hosts. Planting date of corn affected aflatoxin and beauvericin contamination in 2000, and fumonisin concentration in 2001. The observed differences in mycotoxin contamination of the grains, which are likely due to host-specific differences in susceptibility to pre-harvest mycoflora, may affect food safety when the crops are grown under stress conditions.     

Rust and Downy Mildew Resistance in Pearl Millet (Pennisetum glaucum) Mediated by Heterologous Expression of the afp Gene from Aspergillus giganteus

The cDNA encoding the antifungal protein AFP from the mould Aspergillus giganteus was introduced into two pearl millet (Pennisetum glaucum) genotypes by particle bombardment. Stable integration and expression of the afp gene was confirmed in two independent transgenic T₀ plants and their progeny using Southern blot and RT-PCR analysis. In vitro infection of detached leaves and in vivo inoculation of whole plants with the basidomycete Puccinia substriata, the causal agent of rust disease, and the oomycete Sclerospora graminicola, causal agent of downy mildew, resulted in a significant reduction of disease symptoms in comparison to wild type control plants. The disease resistance of pearl millet was increased by up to 90% when infected with two diverse, economically important pathogens. This is the first report of genetic enhancement of Pennisetum glaucum against fungal infections.     

谷子全生育期抗旱性鉴定及抗旱指标筛选

作物全生育期抗旱性对发掘和利用抗旱品种和抗旱基因至关重要,但谷子全生育期抗旱鉴定至今未有报道,抗旱鉴定缺乏鉴定指标。本试验在干旱池模拟干旱条件下,对苗期抗旱性表现不同的谷子品种进行了全生育期抗旱性研究,调查分析了根干重等形态和生理性状在干旱胁迫条件下的变化;采用相关和灰色关联度等方法,分析这些指标与抗旱性(DRI)的关系。结果表明,相对根冠比、相对单穗粒重和灌浆期光合速率、蒸腾速率同抗旱性表现极显著相关,可以作为谷子全生育期抗旱性鉴定的指标;而相对根干重、相对单穗重、相对株高和气孔导度则可以作为谷子全生育期抗旱性鉴定的参考指标;在供试的品种中,红根谷和大齐头白表现了良好的综合抗旱性。本文还讨论了抗旱性的复杂性以及不同性状对干旱胁迫的反应,所建立的指标对谷子全生育期抗旱鉴定具有指导意义。     

黍稷的名实考证及规范

黍稷是起源于中国最古老的作物,糯者为黍,粳者为稷。长期以来对黍稷的称谓一直不能统一,特别是对稷的称谓在农史界一直争论不休,难以定论。本文从黍稷的起源演化过程、细胞学和遗传学的研究、黍稷是人类最早驯化的作物、我国甲骨文和古农书的记载等方面,论证了黍稷的起源早于粟。并以此为据,进一步辩证了稷不是粟,同时指出将黍稷称为软糜和硬糜、糜黍、糜子、黍子等不同称谓的不足之处,进而认为以黍稷作为规范称谓为好。     

Mg^2+介导底物亲和力的改变增加黍子过氧化物酶的磷酸酶活性

黍子过氧化物酶(proso millet peroxidase,PmPOD)具有磷酸酶活性,可以断裂DNA中磷酸二酯键及脱氧核糖核苷酸(dNMPs)中磷酸单酯键。在此反应过程中,Mg^2+显著增强PmPOD的磷酸酶活性,但其具体的机制尚不明确。本文采用紫外-可见分光光谱法和荧光光谱法,研究了以dNMPs为底物时,Mg^2+对PmPOD磷酸酶活性的影响,并对其反应机制进行了初步的探究。紫外-可见分光光度法结果表明:Mg^2+介导了PmPOD与底物的相互作用,但Mg^2+并未直接与PmPOD发生相互作用。荧光光谱进一步表明,在Mg^2+存在的情况下,dNMPs对PmPOD内源荧光淬灭方式发生变化,由动态淬灭转变为静态淬灭。同时还发现,dNMPs与PmPOD的结合常数Ka增加约2~10倍(与不存在Mg^2+条件相比),依次为:KadCMP>KadGMP>KadTMP>KadAMP。高效液相色谱表明,Mg^2+可增强PmPOD水解dNMPs的速率3~13倍,且水解速率VdCMP>VdGMP>VdTMP>VdAMP,与结合常数的变化一致。因此,我们得出结论,PmPOD发挥磷酸酶活性时,Mg^2+首先与dNMPs形成中间产物,这一中间产物更适合与PmPOD形成复合物,增大了底物dNMPs与PmPOD结合常数,进而加速了PmPOD水解dNMPs。本研究为Mg^2+在过氧化物酶催化DNA水解的机制提供了相关依据,为研究金属离子增强蛋白酶活性的机制提供了理论基础。