Heterotrimeric G protein Gβ‐deficient mutants in rice and maize display constitutive immune responses, whereas Arabidopsis Gβ mutants show impaired defense, suggesting the existence of functional differences between monocots and dicots. Using CRISPR/Cas9, we produced one hemizygous tomato line with a mutated SlGB1 Gβ gene. Homozygous slgb1 knockout mutants exhibit all the hallmarks of autoimmune mutants, including development of necrotic lesions, constitutive expression of defense‐related genes, and high endogenous levels of salicylic acid (SA) and reactive oxygen species, resulting in early seedling lethality. Virus‐induced silencing of Gβ in cotton reproduced the symptoms observed in tomato mutants, confirming that the autoimmune phenotype is not limited to monocot species but is also shared by dicots. Even though multiple genes involved in SA and ethylene signaling are highly induced by Gβ silencing in tomato and cotton, co‐silencing of SA or ethylene signaling components in cotton failed to suppress the lethal phenotype, whereas co‐silencing of the oxidative burst oxidase RbohD can repress lethality. Despite the autoimmune response observed in slgb1 mutants, we show that SlGB1 is a positive regulator of the pathogen‐associated molecular pattern (PAMP)‐triggered immunity (PTI) response in tomato. We speculate that the phenotypic differences observed between Arabidopsis and tomato/cotton/rice/maize Gβ knockouts do not necessarily reflect divergences in G protein‐mediated defense mechanisms.

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This study was conducted with the aim of determining the factors that affect the growth and development of in vitro-derived pepper plantlets variety Vinh Linh in greenhouse. The results indicated that gradual adaptation of in vitro plantlets to ex vitro environment by placing enclosed plantlets-containing culture vessels in greenhouse for 2 weeks improved the survival and growth of pepper plantlets upon transfer to acclimatization substrate. The plantlets were required to reach the weight of 0.7-0.9 g before transplanting into nursery bags containing substrate that was red soil:cow dung:coconut husk:rice husk (5:2:2:1). Alternative application of NPK 0.2% and foliar fertilizer Nupe 0.2% every 2 weeks positively affected plant growth and the plants were ready for transplanting into the field after about 5 months. The research results establish an acclimatization protocol for pepper plantlets post-in vitro stage that helps to complete the protocol for pepper production using micropropagation method.