Moseyko Nick, Zhu Tong, Chang Hur-Song, Wang Xun, Feldman Lewis J
Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA 94720-3102, USA.
Plant Physiol. 2002 Oct;130(2):720-8. doi: 10.1104/pp.009688.
Studies of plant tropisms, the directed growth toward or away from external stimuli such as light and gravity, began more than a century ago. Yet biochemical, physiological, and especially molecular mechanisms of plant tropic responses remain for the most part unclear. We examined expression of 8,300 genes during early stages of the gravitropic response using high-density oligonucleotide probe microarrays. Approximately 1.7% of the genes represented on the array exhibited significant expression changes within the first 30 min of gravity stimulation. Among gravity-induced genes were a number of genes previously implicated to be involved in gravitropism. However, a much larger number of the identified genes have not been previously associated with gravitropism. Because reorientation of plants may also expose plants to mechanical perturbations, we also compared the effects of a gentle mechanical perturbation on mRNA levels during the gravity response. It was found that approximately 39% of apparently gravity-regulated genes were also regulated by the mechanical perturbation caused by plant reorientation. Our study revealed the induction of complex gene expression patterns as a consequence of gravitropic reorientation and points to an interplay between the gravitropic and mechanical responses and to the extreme sensitivity of plants to even very gentle mechanical perturbations.
对植物向性运动（即朝着或背离诸如光和重力等外部刺激的定向生长）的研究始于一个多世纪以前。然而，植物向性反应的生化、生理，尤其是分子机制在很大程度上仍不清楚。我们使用高密度寡核苷酸探针微阵列研究了重力反应早期8300个基因的表达情况。阵列上所代表的基因中约1.7%在重力刺激的最初30分钟内表现出显著的表达变化。在重力诱导基因中，有许多基因先前被认为与向重力性有关。然而，大量已鉴定的基因此前并未与向重力性相关联。由于植物重新定向也可能使植物受到机械干扰，我们还比较了轻微机械干扰对重力反应过程中mRNA水平的影响。结果发现，约39%明显受重力调节的基因也受到植物重新定向引起的机械干扰的调节。我们的研究揭示了重力重新定向导致的复杂基因表达模式的诱导，并指出了向重力性和机械反应之间的相互作用，以及植物对甚至非常轻微的机械干扰的极端敏感性。
