The pip1s Quintuple Mutants Demonstrate the Essential Roles of PIP1s in the Plant Growth and Development of Arabidopsis

Plasma membrane intrinsic proteins (PIPs) transport water, CO2 and small neutral solutes across the plasma membranes. In this study, we used the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 system (CRISPR/Cas9) to mutate PIP1;4 and PIP1;5 in a pip1;1,2,3 triple mutant to generate a pip1;1,2,3,4,5 (pip1s(-)) quintuple mutant. Compared to the wild-type (WT) plant, the pip1s(-) mutants had smaller sized rosette leaves and flowers, less rosette leaf number, more undeveloped siliques, shorter silique and less seeds. The pollen germination rate of the pip1s(-) mutant was significantly lower than that of the WT and the outer wall of the pip1s(-) mutant's pollen was deformed. The transcriptomic analysis showed significant alterations in the expression of many key genes and transcription factors (TFs) in the pip1s(-) mutant which involved in the development of leaf, flower and pollen, suggesting that the mutant of PIP1s not only directly affects hydraulics and carbon fixation, but also regulates the expression of related genes to affect plant growth and development.

Automated summary

The study used CRISPR/Cas9 system to mutate PIP1;4 and PIP1;5 genes in a triple mutant, generating a quintuple mutant. The pip1s(-) mutants exhibited smaller leaves and flowers, fewer developed siliques, shorter silique length, and decreased seed production compared to the wild-type plant. The mutant also showed significantly lower pollen germination rate and deformed pollen outer wall, along with transcriptomic changes in key genes related to leaf, flower, and pollen development.