Identification of double/twin bolled and bicolor unit ‘cluster’ in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. cotton

Cultivated tetraploid Gossypium hirsutum L. (Malvaceae) cotton has been characterized as having one flower at a primordia. In a strain (CSH-13) of Gossypium hirsutum cotton, four plants out of 103 had two to three double bolls or twin bolls/plant during 2003–2004 crop season at CICR regional station, Sirsa, Haryana, India. Progeny evaluation in 2004 and 2005 crop seasons indicated that plants raised from seeds harvested from double bolls/twin bolls produced plants bearing double bolls only and plant progeny raised from the seed of single bolls from these mutant plants produced two to three double bolls per plant similar to the parent. Progeny testing revealed that double boll formation is the result of spontaneous mutation and environment does not influence its expression. The mutant is early in maturity by 10–15 days, naked seeded and possesses comparable agronomic characters with normal plants. Another spontaneous mutant of Gossypium hirsutum having more than three appendages originating from primordia.: four bolls one leaf, three bolls one leaf, two bolls two leaves, one boll three leaves were obtained from the population of CISV-13 strain in crop season 2003. These appendage groups have been described as bicolor unit by Clemens Bayer, [Zur Infloreszenzmorphologie der Malvales. Dissertations Botany 212 (1994)] and cluster mutant by Russell and Luther [J Cott Sci 6 (2002) 115]. One to three bolls in a cluster or bicolor unit were observed without formation of seeds and lint. About one-third of the total bolls on the mutant plant were of this type. In progeny testing during 2004 and 2005 crop seasons, this mutant produced plants exclusively with more than three appendages revealing that plants identified in 2003 were due to spontaneous mutation. This mutant was also early and naked seeded. Many of the other characters of the mutant plants were comparable with the wild type plants of the strain. Both the mutants were observed having economic impact due to their better yielding ability as compare to respective parents.     

棉花胚性愈伤的快速诱导和繁殖

棉花（Gossypium hirsutum L.）是世界上最重要的商业纤维作物。与其他作物相比,棉花再生体系较难。通过生物技术对棉花进行遗传改良往往受制于缺乏高效的再生体系。高效、快速的再生体系的开发有助于提高棉花转化效率。在0.10 mg/L的吲哚乙酸（IAA）、0.09 mg/L细胞分裂素（KT）和0.09 mg/L 2,4-二氯苯氧乙酸（2,4-D）的MSB5培养基上产生高效愈伤组织。胚性愈伤组织可在愈伤组织基础上与SM2培养基中诱导出来,也可在“M1-SM1-SM2”培养基交替使用过程中诱导出来。利用此方法可在2~3月内诱导出胚性愈伤,大大缩短再生周期。胚性愈伤在PM1或PM2培养基中可以维持良好的再生状态。可见建立的快速诱导和繁殖胚性愈伤的方法可以用于棉花基因工程遗传改良。     

Response of cotton root growth and yield to root restriction under various water and nitrogen regimes

Water and nitrogen (N) are two major factors limiting cotton growth and yield. The ability of plants to absorb water and nutrients is closely related to the size of the root system and the rooting space. Better understanding of the physiological mechanisms by which cotton (Gossypium hirsutum L.) adapts to water and N supply when rooting volume is restricted would be useful for improving cotton yield. In this study, cotton was grown in soil columns to control rooting depth to either 60 cm (root‐restriction treatment) or 120 cm (no‐root‐restriction treatment). Four water–N combinations were applied to the plants: (1) deficit irrigation and no N fertilizer (W₀N₀), (2) deficit irrigation and moderate N fertilizer rate (W₀N₁), (3) moderate irrigation and no N fertilizer (W₁N₀), and (4) moderate irrigation and moderate N fertilizer rate (W₁N₁). Results revealed that root restriction reduced root length density (RLD), root volume density (RVD), root mass density (RMD), superoxide dismutase (SOD) activity, nitrate reductase (NR) activity, total plant biomass, and root : shoot ratio. In contrast, root restriction increased aboveground biomass and yield. The RLD, RVD, RMD, and root : shoot ratio decreased in the order W₀N₀ > W₁N₀ > W₀N₁ > W₁N₁ in both the root‐restriction and no‐root‐restriction treatments. However, the opposite order (i.e., W₁N₁ > W₀N₁ > W₁N₀ > W₀N₀) was observed for SOD activity, NR activity, aboveground biomass, and seed yield. Our results suggest that, when N and water supplies are adequate, root restriction increases both root activity and the availability of photosynthates to aboveground plant parts. This increases shoot growth, the shoot : root ratio, and yield.     

海岛棉GbMYB25基因的克隆及表达分析

根据陆地棉GhMYB25的序列,设计1对引物,通过RT-PCR技术从海岛棉品种新海21号中克隆了1个同源基因,命名为GbMYB25。GbMYB25基因具有1个930bp的开放阅读框,编码309个氨基酸,预测分子量约为34.762ku,等电点为8.08,推测的氨基酸序列中含有2个高度保守的SANT结构域。GbMYB25基因序列包含2个内含子。氨基酸序列比对表明,该蛋白和其他高等植物的MYB蛋白有较高的同源性。进化树分析表明,GbMYB25基因和陆地棉GhMYB25基因处在同一进化树分支。亚细胞定位表明GbMYB25基因在细胞核中表达,实时荧光定量PCR结果表明GbMYB25基因在胚珠(0doa)、纤维(5dpa)和叶片中的表达量较高。以上结果表明,GbMYB25转录因子可能参与棉花纤维发育。     

陆地棉种内杂种F_2不同叶型生产力的研究

研究了3个正常叶型材料与鸡脚叶型材料杂交得到的杂种2代结果表明,选用适当亲本组配的杂交组合,不仅F_1能获得高产,F_2也有一定利用价值,其中尤以鄂棉15×鸡-2最好。对几个农艺性状与产量的相关分析表明,在条裂叶型、正常叶型材料中,果枝数、果节数与皮棉产量达显著正相关,条裂叶型F_2的纤维长度高于正常叶型。以合理正常叶植株与条裂叶植株的比例和适当的栽培措施改善农艺性状,便能提高F_2的产量和纤维品质。     

棉属诸种植株茸毛与其地理分布的关系

通过时棉属33个野生二倍体种和6个四倍体种植株茸毛与其分布地理纬度关系的分析看出,分布在南、北回归线间的棉种植株多茸毛;分布在南、北回归线附近的棉种植株稀毛或近光滑;分布在南回归线以南,北回归线以北的棉种植株光滑无毛。这种离开赤道愈远,棉种植株茸毛越少以至光滑的现象,体现了棉属诸种植株茸毛与地理分布的规律性。而那些不合这一规律的棉种,正是在分布、起源和进化上长期有争议的棉种。根据棉种植株茸毛与地理分布的规律性,笔者认为戴维逊氏棉是克劳茨基棉的变种;四倍体棉种是多元发生。     

陆地棉转录因子的染色体定位

利用植物转录因子PTFD数据库1 116条陆地棉转录因子DNA序列设计的1 455对SSR引物,筛选陆地棉品种/品系渝棉1号、中棉所35、7235和T586,获得66对多态性引物。它们涉及到27个转录因子家族的64个转录因子,其中渝棉1号与中棉所35间23对多态性引物,渝棉1号与T586间30对多态性引物,渝棉1号与7235间33对多态性引物。以多态性引物检测对应重组近交系群体,共获得93个位点。其中,(渝棉1号×中棉所35)群体23个位点,(渝棉1号×T586)群体32个位点,(渝棉1号×7235)群体38个位点。利用转录因子SSR位点与实验室已定位的SSR位点进行遗传连锁分析,将84个位点定位于23条染色体上,其中32个位点分布于A染色体组,52个位点分布于D染色体组。     

陆地棉棉叶蝉数量气象预报模型研究

为了有效地防治棉叶蝉,促进华南棉花发展,研究了10个陆地棉品种田间棉叶蝉数与温度、降水的关系,建立了11个陆地棉棉叶蝉数量气象条件预报模型,其中3个分别可以较准确地预报抗虫棉95-1、石家庄428 2个品种和10品种平均单株棉叶蝉数。品种间棉叶蝉发生轻重对温度、降水的反应不同,为了提高预报精确度,每个品种应各建立一个棉叶蝉预报模型。     

盐胁迫下棉花叶片差异蛋白表达的分析

以耐盐的陆地棉品种中07为研究材料,在其生长的三叶期,用未处理和0.4%NaCl胁迫处理24h的幼苗,分别提取其叶片全蛋白。通过等电聚焦和第二向SDS-PAGE技术获得完整的棉花叶片总蛋白图,利用ImageMaste-2DElite5.0软件分析各个差异蛋白在对照和0.4%NaCl胁迫24h后棉花叶片中的相对表达量,并选取质量好、实验重复性高的10个特异的差异表达蛋白质点进行基质辅助激光解吸电离串联飞行时间质谱(MALDI-TOF-TOF/MS)鉴定。结果表明,从对照和盐胁迫处理的双向电泳图谱中共检测到24个差异蛋白质点,这些差异蛋白质点的等电点分布集中在5.0～6.5之间,分子量分布集中在40.0～110.0kD之间;进一步质谱(MALDI-TOF-TOF/MS)分析鉴定的10个差异蛋白质点,其中4个蛋白质点获得了鉴定结果,这4个差异表达蛋白质点分别为1,5-二磷酸核酮糖羧化/氧化激酶α2(编号4)、1,5-二磷酸核酮糖羧化酶/氧化酶大亚基(编号5)、未知蛋白产物(编号19)和OEE2(编号32)。我们初步推测OEE2和1,5-二磷酸核酮糖羧化酶/氧化酶可能与棉花耐盐胁迫特性有关。     

从多毛野生番茄中初步鉴定出一个抗美洲斑潜蝇的显性基因

美洲斑潜蝇(LiriomyzasativaeBlandchard)是危害番茄生产的主要害虫之一,从番茄近缘野生种中挖掘优异的抗斑潜蝇基因,并研究抗虫基因的遗传,是番茄抗虫遗传改良的重要基础。将筛选到的高抗美洲斑潜蝇的野生多毛番茄(L.hirsutum)材料LA2329,与高感美洲斑潜蝇栽培番茄早粉2号杂交,并用早粉2号为母本与杂种F1回交,通过对各世代抗斑潜蝇的人工接种鉴定,初步判定该抗性由单显性基因控制。番茄属中由单显性基因控制的对斑潜蝇抗性,目前尚未见报道。该抗性基因的发现,将为今后番茄抗斑潜蝇育种提供宝贵资源,有望在不远的将来通过标记辅助育种手段而引入栽培番茄,为我国番茄生产中害虫的防治提供环保、经济而有效的科技支撑。