State-of-the-art and novel developments of in vivo haploid technologies

Abstract

The ability to generate (doubled) haploid plants significantly accelerates the crop breeding process. Haploids have been induced mainly through the generation of plants from cultivated gametophic (haploid) cells and tissues, i.e., in vitro haploid technologies, or through the selective loss of a parental chromosome set upon inter- or intraspecific hybridization. Here, we focus our review on the mechanisms responsible for the in vivo formation of haploids in the context of inter- and intraspecific hybridization. The application of a modified CENH3 for uniparental genome elimination, the IG1 system used for paternal as well as the BBM-like and the patatin-like phospholipase essential for maternal haploidy induction are discussed in detail.

Site‐directed mutagenesis in bread and durum wheat via pollination by cas9/guide RNA‐transgenic maize used as haploidy inducer

“…This technology, however, is limited by long and costly regulatory evaluation processes owing to publicly overrated method‐specific risks. As another option, the use of meiotically recombinant and genetically fixed doubled haploids proved very useful for accelerating crop improvement (Kalinowska et al ., 2019). Viable methods of in planta haploid induction via uniparental genome elimination are available in species such as Arabidopsis through modification of CENTROMERIC HISTONE 3 ( CENH3 ) (Ravi and Chan, 2010), in maize and rice via knockout of a sperm‐specific phospholipase gene (Kelliher et al ., 2017; Yao et al ., 2018), and in wheat through intergeneric crossing with maize (Laurie and Bennett, 1988).…”

Unequal contribution of two paralogous centromeric histones to function the cowpea centromere

“…A method to generate doubled-haploids could accelerate the breeding of new, improved, cowpea cultivars. In order to establish a haploidization method based on the manipulation of the centromere (Kalinowska et al 2019), we analyzed the centromere composition of this species.…”

Centromere histone H3- and phospholipase-mediated haploid induction in plants

“…1) [40]. Attempts by N-terminal tail editing have been performed in diverse species [49], and HI has been successfully achieved in maize [48], tomato and rice [50]. Although the HI rates are relatively low (0.065–0.86% in maize, 0.2–2.3% in tomato, and 0.3–1.0% in rice), these experiments demonstrated the feasibility of HI by engineering the CENH3 N-terminal tail in monocotyledonous crop plants.

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