CS-17-3 - Corn RHS2, an endogenous tassel-specific siRNA-mediated glyphosate inducible male sterility system for hybrid seed production
Monday, July 16
3:58 PM - 4:18 PM
Hybrid crops produce higher yields than their inbred parents due to heterosis. For high purity of hybrid seeds, it is critical to eliminate self-pollination. Manual or mechanical removal of male parts (such as detasseling in maize) is labor-intensive, fuel and time-consuming, and can cause physical damage to female plants, resulting in significant seed yield reductions. Many male-sterility systems either require a maintainer for male-sterile line propagation or are often affected by environmental factors. Roundup® Hybridization System (RHS) utilizes glyphosate to induce male sterility, which effectively eliminates the need for maintainer lines and removal of male parts for commercial hybrid seed production. The first-generation RHS (RHS1) is based on low expression of a glyphosate-insensitive 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) in pollen. This talk presents the second-generation RHS (RHS2) technology built on RNA interference (RNAi) combined with CP4 EPSPS. RHS2 utilizes endogenous male tissue-specific small interfering RNAs (mts-siRNAs) to trigger cleavage of the CP4 EPSPS mRNA specifically in maize tassels, resulting in glyphosate-sensitive male cells due to lack of the CP4 EPSPS protein. Male sterility is then induced by glyphosate application at the stages critical for pollen development, and the male-sterile plants are used as the female parent to produce hybrid seed. The endogenous mts-siRNAs are conserved across maize germplasms, and the inducible male sterility was replicated in representative germplasms through introgression of a CP4 EPSPS transgene containing the mts-siRNA target sequence. This technology combines the relative simplicity and convenience of a systemic herbicide spray methodology with targeted protein expression to create an inducible male sterility system for industrial production of row crop hybrid seeds in an environmentally-independent manner.
Heping Yang – Monsanto Company; Youlin Qi – Monsanto Company; Jintai Huang – Monsanto Company; Sergey Ivashuta – Monsanto Company; Yuanji Zhang – Monsanto Company; Oscar Sparks – Monsanto Company; Jiyan Ma – Monsanto Company; Brook Van Scoyoc – Monsanto Company; Amy Caruano-Yzermans – Monsanto Company; Jennifer King-Sitzes – Monsanto Company; Xin Li – Monsanto Company; Aihong Pan – Monsanto Company; Marty Stoecker – Monsanto Company; Elizabeth Wiggins – Monsanto Company; Rita Varagona – Monsanto Company