n nnnThe role of gibberellins (GAs) in regulation of lateral rootdevelopment is poorly understood. We show that GA-deficient(35S:PcGA2ox1) and GA-insensitive (35S:rgl1) transgenic Populusexhibited increased lateral root proliferation and elongationunder in vitro and greenhouse conditions, and these effectswere reversed by exogenous GA treatment. In addition, RNA interferencesuppression of two poplar GA 2-oxidases predominantly expressedin roots also decreased lateral root formation. GAs negativelyaffected lateral root formation by inhibiting lateral root primordiuminitiation. A whole-genome microarray analysis of root developmentin GA-modified transgenic plants revealed 2069 genes with significantlyaltered expression. The expression of 1178 genes, includinggenes that promote cell proliferation, growth, and cell wallloosening, corresponded to the phenotypic severity of the roottraits when transgenic events with differential phenotypic expressionwere compared. The array data and direct hormone measurementssuggested crosstalk of GA signaling with other hormone pathways,including auxin and abscisic acid. Transgenic modification ofa differentially expressed gene encoding an auxin efflux carriersuggests that GA modulation of lateral root development is atleast partly imparted by polar auxin transport modification.These results suggest a mechanism for GA-regulated modulationof lateral root proliferation associated with regulation ofplant allometry during the stress response.展开▼
机译：ABSTRACTn n
n TOP n <字体颜色= 464c53>抽象 n 介绍 n 结果与讨论 n 方法 n 参考文献 n < / TABLE> n nnn对于赤霉素（GAs）在调节侧根 发育中的作用了解甚少。我们显示GA缺陷型 （ 35S：PcGA2ox1 ）和GA不敏感（ 35S ： rgl1 ）转基因<在体外和温室条件下，I>杨 表现出增加的侧根增殖和伸长 ，而这些作用 被外源GA逆转治疗。此外，RNA干扰 抑制了两个主要在根中表达的 GA 2-氧化酶，也减少了侧根的形成。 GAs通过抑制侧根原基 的起始而对 产生负面影响。全基因组微阵列分析遗传修饰的转基因植物中根发育 揭示了2069个具有显着 改变表达的基因。 1178个基因的表达，包括促进细胞增殖，生长和细胞壁 松动的 基因，与根部 性状的表型严重程度相对应。比较具有差异表型表达的转基因事件 。阵列数据和直接激素测量 建议GA信号与其他激素途径（ ）包括生长素和脱落酸的串扰。对 编码植物生长素外排载体 的差异表达基因的转基因修饰建议，侧向根发育的GA调节至少部分是由极性植物生长素转运引起的 这些结果表明，在胁迫反应期间，GA调节侧根增殖的机制与植物 异体结膜的调节相关。 >
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School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931-1295;
Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon 97331-5752;
Warnell School of Forestry and Natural Resources, Department of Genetics, University of Georgia, Athens, Georgia 30602-2152;
National Engineering Laboratory for Tree Breeding, College of Life Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China;
School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931-1295;
National Engineering Laboratory for Tree Breeding, College of Life Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China;
School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931-1295;
