The local auxin distribution characteristics in the roots, stems, and leaves of stably transformed plantlets of trifoliate orange (Poncirus trifoliata) with auxin reporter system DR5::GUS-YFP were elucidated in this research. The auxin response maxima could be observed in the apex of the root tip, primary phloem of the tender stem, and the margin of the young leaves according to the activity of the β-glucuronidase (GUS) reporter gene triggered by the auxin responsive DR5 promoter. Auxin responses in the apex of the root tips increased when treated with synthetic auxin 1-naphthylacetic acid (NAA), but decreased when treated with the auxin polar transportation inhibitor 2,3,5-triiodobenzoic acid (TIBA). These results indicated that the DR5 reporter system worked in P. trifoliata for auxin distribution and response observation. Trifoliate orange is highly susceptible to citrus canker disease. Auxin accumulation was observed visually in the invasion sites of the detached leaves inoculated with Xanthomonas axonopodis pv. citri (Xac) by GUS staining; the upregulated expression of the YFP, GH3.1, GH3.9, and SAUR genes assessed by quantitative real-time PCR (qRT-PCR) also identified auxin accumulation in the inoculated tissues following Xac infection. Overall, these findings indicated that the plantlets of P. trifoliata engineered with the auxin reporter gene provided a promising system for studying auxin responses during Xac infection.

本研究阐明了用生长素报告系统DR5 :: GUS-YFP稳定转化的三叶橙（Poncirus trifoliata）幼苗的根，茎和叶中的局部生长素分布特征。根据生长素反应性DR5引发的β-葡萄糖醛酸酶（GUS）报告基因的活性，可以在根尖的根尖，嫩茎的初生韧皮部和幼叶的边缘观察到生长素反应最大值。启动子。用合成生长素1-萘乙酸（NAA）处理时，根尖顶点的生长素响应增加，而用生长素极性转运抑制剂2,3,5-三碘代苯甲酸（TIBA）处理则下降。这些结果表明DR5报告系统在三叶假单胞菌中可用于生长素的分布和响应观察。三叶橙对柑橘溃疡病极易感。肉眼观察到轴突黄单胞菌pv接种的离体叶片的侵袭位点生长素的积累。用GUS染色的柠檬（Xac）; YFP，GH3.1，GH3.9和SAUR的表达上调通过定量实时PCR（qRT-PCR）评估的基因还鉴定了Xac感染后被接种组织中的生长素积累。总体而言，这些发现表明，用生长素报告基因工程改造的三叶草的幼苗为研究Xac感染期间的生长素反应提供了一个有希望的系统。