What's happening at IRRI
Friday, November 18, 2016, 01:30pm - 02:30pm
The MATRILINEAL gene triggers in vivo (seed based) haploid induction in maize
Dr. Timothy Joseph Kelliher
Reproductive Biology Lead, Reproductive Biology
Syngenta Crop Protection
1400-1500H, Friday, 18 November 2016
Room A, Umali Building
Reproduction in flowering plants involves double fertilization. Modern plant breeders increasingly seek to circumvent this process to produce doubled haploid (DH) individuals, which derive from the chromosome-doubled cells of the haploid gametophyte. Costly, genotype-dependent tissue culture methods are employed in many crops, while seed-based in vivo DH systems are rare in nature and difficult to manage in breeding programs. The multi-billion dollar maize hybrid seed business, however, is supported by industrial DH pipelines utilizing intra-specific crosses to in vivo haploid inducer males derived from Stock 6, first reported in 1959, followed by colchicine treatment. Despite decades of use, the mode of action remains controversial. Through fine mapping, genome sequencing, genetic complementation and gene editing we establish that haploid induction in maize is triggered by a frame-shift mutation in MATRILINEAL (MTL), and that novel edits lead to a 6.7% haploid induction rate. Pollen RNA-seq profiling identified a suite of pollen-specific genes over-expressed during haploid induction, some of which may mediate the formation of haploid seed. These findings highlight the importance of male gamete components to reproductive success and male genome transmittance. Given the conservation of MTL in the grasses, this discovery may enable development of in vivo haploid induction systems to accelerate breeding in crop plants such as rice.
Rm A, DL Umali Bldg.