CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, Uttar Pradesh, India.
CSIR-Central Institute of Medicinal and Aromatic Plants, Research Centre, Bengaluru, Karnataka, India.
Physiol Plant. 2024 Mar-Apr;176(2):e14276. doi: 10.1111/ppl.14276.
The leaf-specific Catharanthus roseus alkaloid, vindoline, is the major bottleneck precursor in the production of scarce and costly anticancer bisindoles (vincristine and vinblastine). The final steps of its biosynthesis and storage occur in the laticifers. Earlier, we have shown that vindoline content is directly related to laticifer number. Pectin remodeling enzymes, like pectin methylesterase (PME), are known to be involved in laticifer development. A search in the croFGD yielded a leaf-abundant CrPME isoform that co-expressed with a few vindoline biosynthetic genes. Full-length cloning, tissue-specific expression profiling, and in silico analysis of CrPME were carried out. It was found to possess all the specific characteristics of a typical plant PME. Transient silencing (through VIGS) and overexpression of CrPME in C. roseus indicated a direct relationship between its expression and vindoline content. Comparative analysis of transcript abundance and enzyme activity in three familial C. roseus genotypes differing significantly in their vindoline content and laticifer count (CIM-Sushil > Dhawal > Nirmal) also corroborated the positive relationship of CrPME expression with vindoline content. This study highlights the possible role of CrPME, a cell wall remodeling enzyme, in modulating laticifer-associated secondary metabolism.
长春花生物碱，长春质碱，是生产稀缺且昂贵的抗癌双吲哚（长春碱和长春新碱）的主要前体。其生物合成和储存的最后步骤发生在乳汁管中。此前，我们已经证明长春质碱的含量与乳汁管的数量直接相关。众所周知，果胶修饰酶，如果胶甲酯酶（PME），参与乳汁管的发育。在 croFGD 中搜索到一个叶丰富的 CrPME 同工型，它与几个长春质碱生物合成基因共表达。对 CrPME 进行全长克隆、组织特异性表达谱分析和计算机分析。结果表明，它具有典型植物 PME 的所有特征。在长春花中的瞬时沉默（通过 VIGS）和 CrPME 的过表达表明其表达与长春质碱含量之间存在直接关系。对三个在长春质碱含量和乳汁管数量上有显著差异的家族基因型（CIM-Sushil > Dhawal > Nirmal）的转录本丰度和酶活性进行比较分析，也证实了 CrPME 表达与长春质碱含量的正相关。本研究强调了细胞壁修饰酶 CrPME 在调节与乳汁管相关的次生代谢中的可能作用。
