Engineering meiotic recombination pathways in rice

Abstract

Summary In the last 15 years, outstanding progress has been made in understanding the function of meiotic genes in the model dicot and monocot plants Arabidopsis and rice (Oryza sativa L.), respectively. This knowledge allowed to modulate meiotic recombination in Arabidopsis and, more recently, in rice. For instance, the overall frequency of crossovers (COs) has been stimulated 2.3‐ and 3.2‐fold through the inactivation of the rice FANCM and RECQ4 DNA helicases, respectively, two genes involved in the repair of DNA double‐strand breaks (DSBs) as noncrossovers (NCOs) of the Class II crossover pathway. Differently, the programmed induction of DSBs and COs at desired sites is currently explored by guiding the SPO11‐1 topoisomerase‐like transesterase, initiating meiotic recombination in all eukaryotes, to specific target regions of the rice genome. Furthermore, the inactivation of 3 meiosis‐specific genes, namely PAIR1, OsREC8 and OsOSD1, in the Mitosis instead of Meiosis (MiMe) mutant turned rice meiosis into mitosis, thereby abolishing recombination and achieving the first component of apomixis, apomeiosis. The successful translation of Arabidopsis results into a crop further allowed the implementation of two breakthrough strategies that triggered parthenogenesis from the MiMe unreduced clonal egg cell and completed the second component of diplosporous apomixis. Here, we review the most recent advances in and future prospects of the manipulation of meiotic recombination in rice and potentially other major crops, all essential for global food security.

Chromosome Engineering in Tropical Cash Crops

“…The process of meiosis has two purposes: to generate the genetic diversity transmitted by the gametes and to ensure correct segregation of chromosomes [35]. Defects in recombination and meiosis cause sterility [35].…”

“…The process of meiosis has two purposes: to generate the genetic diversity transmitted by the gametes and to ensure correct segregation of chromosomes [35]. Defects in recombination and meiosis cause sterility [35]. In Arabidopsis, meiotic recombination begins with the formation of double-strand breaks (DSBs) in DNA, which is initiated by a topoisomerase-like protein called SPO11-1 and associated proteins such as MTOPVIB, PRD1-3, and DFO [36].…”

“…The study of the formation of meiotic crossovers is important for activities related to plant breeding such as the detection and identification of quantitative trait loci and gene mapping [37]. Infertility results from defects in the formation of crossovers because the homologs segregate randomly during cell division [35]. Thus, at least one crossover must be formed per chromosome pair to ensure the formation of balanced and viable gametes [35].…”

“…Infertility results from defects in the formation of crossovers because the homologs segregate randomly during cell division [35]. Thus, at least one crossover must be formed per chromosome pair to ensure the formation of balanced and viable gametes [35].…”

“…Another yet theoretical possibility for crops would be to induce an inversion to create new linkage groups and purposely suppress recombination [40] (see Figure 2D). Suppression of meiotic recombination is also observed during apomixis, a form of reproduction characterized by deregulation of meiosis during embryo sac formation [35], development of the embryo in a fertilization-independent way [35], and formation of viable endosperm in a fertilization-dependent or -independent way [35]. Apomixis is an effective strategy to retain genome-wide parental heterozygosity; recently, apomixis was successfully engineered in rice to facilitate clonal propagation of hybrids by seed [52].…”