The application of temperature sensitivity CRISPR/LbCpf1 (LbCas12a) mediated genome editing in allotetraploid cotton (G. hirsutum) and creation of nontransgenic, gossypol‐free cotton

Cotton (Gossypium hirsutum) is an allotetraploid species and a typical thermophilic crop that can survive and grow well under temperatures up to 45 °C. CRISPR/LbCpf1 (LbCas12a) is a temperature‐sensitive system for plant genome editing (Malzahn et al., 2019) and has been successfully applied in species such as rice, soya bean, tobacco, maize and cotton (Lee et al., 2019; Li et al., 2018; Tang et al., 2017; Xu et al., 2019). In order to improve LbCpf1 efficiency and determine the optimum temperature for cotton genome editing, we investigated the effects of different temperatures on LbCpf1 activity and genome editing efficiency. [...]we created nontransgenic and glandless cotton plants with seeds free of gossypol, representing a valuable germplasm resource for cotton breeding. With the increase of temperature, the bleaching phenotype of leaves becomes more obvious in T1 LbCpf1‐GhCLA1 transgenic plants grown in the field. (b) Phenotypes of T1 cotton plants with the target mutations in the GhCLA1 gene, grown at different temperatures.