LOW GERMINATION STIMULANT 1 (LGS1) plays an important role in strigolactones (SLs) biosynthesis and Striga resistance in sorghum but the catalytic function remains unclear. Using the recently developed SL-producing microbial consortia, we examined the activities of sorghum MAX1 analogs and LGS1. Surprisingly, SbMAX1d (accession # XP_002458367) synthesized 18-hydroxy-carlactonoic acid (18-hydroxy-CLA) directly from carlactone (CL) through four-step oxidations, and addition of LGS1 led to the synthesis of both 5-deoxystrigol (5DS) and 4-deoxyorobanchol (4DO). Further biochemical characterization found that LGS1 functions after SbMAX1d by converting 18-hydroxy-CLA to 18-sulphate-CLA to provide an easier leaving group to afford a spontaneous formation of 5DS and 4DO. The unique functions of SbMAX1 and LGS1 imply a previously unknown synthetic route towards strigolactones.

中文翻译：

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高粱中独特的涉及磺基转移酶的独脚金内酯生物合成路线

低发芽刺激物 1 (LGS1) 在独脚金内酯 (SLs) 生物合成和独脚金中起重要作用高粱抗性，但催化功能尚不清楚。使用最近开发的产 SL 微生物群落，我们检查了高粱 MAX1 类似物和 LGS1 的活性。令人惊讶的是，SbMAX1d（登录号 XP_002458367）通过四步氧化直接从卡拉内酯 (CL) 合成了 18-羟基-卡拉内酯酸 (18-羟基-CLA)，并且添加 LGS1 导致了 5-脱氧独脚金醇 (5DS) 的合成和 4-脱氧班胆 (4DO)。进一步的生化表征发现 LGS1 在 SbMAX1d 之后起作用，通过将 18-羟基-CLA 转化为 18-硫酸盐-CLA 以提供更容易离去的基团，从而自发形成 5DS 和 4DO。SbMAX1 和 LGS1 的独特功能暗示了一条以前未知的独脚金内酯合成路线。