Data from: Forward chemical genetic screens in Arabidopsis identify genes that influence sensitivity to the phytotoxic compound sulfamethoxazole

BACKGROUND: The sulfanilamide family comprises a clinically important group of antimicrobial compounds which also display bioactivity in plants. While there is evidence that sulfanilamides inhibit folate biosynthesis in both bacteria and plants, the complete network of plant responses to these compounds remains to be characterized. As such, we initiated two forward genetic screens in Arabidopsis in order to identify mutants that exhibit altered sensitivity to sulfanilamide compounds. These screens were based on the growth phenotype of seedlings germinated in the presence of the compound sulfamethoxazole (Smex). RESULTS: We identified a mutant with reduced sensitivity to Smex, and subsequent mapping indicated that a gene encoding 5-oxoprolinase was responsible for this phenotype. A mutation causing enhanced sensitivity to Smex was mapped to a gene lacking any functional annotation. CONCLUSIONS: The genes identified through our forward genetic screens represent novel mediators of Arabidopsis responses to sulfanilamides and suggest that these responses extend beyond the perturbation of folate biosynthesis.

研究背景：磺胺类家族是一类临床上具有重要价值的抗菌化合物，同时在植物中也表现出生物活性。尽管已有研究证实磺胺类化合物可在细菌与植物体内抑制叶酸生物合成，但植物对这类化合物的完整应答网络仍有待解析。为此，我们在拟南芥（Arabidopsis）中开展了两项正向遗传筛选，以鉴定对磺胺类化合物敏感性发生改变的突变体；本次筛选以在磺胺甲恶唑（sulfamethoxazole, Smex）存在条件下萌发的幼苗生长表型为筛选依据。
研究结果：我们筛选得到一株对Smex敏感性降低的突变体，后续遗传定位显示，该表型由一个编码5-氧代脯氨酸酶（5-oxoprolinase）的基因突变所导致。另一株对Smex敏感性增强的突变体，其突变位点被定位至一个尚无任何功能注释的基因。
研究结论：本研究通过正向遗传筛选所鉴定的基因，是拟南芥应答磺胺类化合物的新型介导因子，同时表明植物对这类化合物的应答过程并不局限于叶酸生物合成的扰动。