Evidence for thermosensitivity of the cotton (Gossypium hirsutum L.) immature fiber (im) mutant via hypersensitive stomatal activity

Authors: Kim, Hee-Jin; KATO, NAOHIRO - Louisiana State University; NDATHE, RUTH - Louisiana State University; Thyssen, Gregory; JONES, DON - Cotton, Inc; RATNAYAKA, HARISH - Louisiana State University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2021
Publication Date: 12/13/2021
Citation: Kim, H.J., Kato, N., Ndathe, R., Thyssen, G.N., Jones, D.C., Ratnayaka, H. 2021. Evidence for thermosensitivity of the cotton (Gossypium hirsutum L.) immature fiber (im) mutant via hypersensitive stomatal activity. PLoS ONE. 16(12):e0259562. https://doi.org/10.1371/journal.pone.0259562.
DOI: https://doi.org/10.1371/journal.pone.0259562

Interpretive Summary: The thickness of cotton fiber cell wall is a major property determining lint yield, fiber quality, and textile performance. An immature fiber (im) mutant producing thin-walled fibers and its isogeneic wild type cotton generating thick-walled fibers have become cotton models for studying regulatory mechanisms of fiber wall development. To better understand the mechanisms that control cell wall development, the effect of environmental conditions in addition to a genetic mutation on cell wall development was compared between fiber and non-fiber tissues of the two cotton plants. Comprehensive analyses of growth-related phenotypes, biomass, photosynthetic response, and transcriptomic files showed that high temperature stress in addition to a genetic mutation was required for inducing the immature fiber mutant phenotype. The results also suggested that the genetic mutation of the im plants may cause hypersensitivity to high temperature and heat stress and reduced abiotic stress tolerance. It also provided an insight into how abiotic stress triggered and jointly amplified the effect of the mutation in the im plants.

Technical Abstract: The thickness of fiber cell wall is a key determinant of cotton quality and textile performance. How a combination of genetic and environmental factors affects fiber wall thickness is not well understood. The fiber wall of immature fiber (im) cotton mutant is thinner than its near isogenic wild type, Texas marker-1 (TM-1). The availability of the near isogenic lines (NILs) provides a unique way for determining regulatory mechanisms of fiber cell wall development. To test environmental effects, growth-related phenotypes were compared in fiber and non-fiber tissues of the NILs grown under different growth conditions. Grown in field conditions with environmental stress, fiber cell wall thickness, leaf biomass, and specific leaf mass were all reduced in im than in TM-1. In contrast, little differences were detected when they were grown under an optimum growth condition. At near optimum temperatures in the field, im leaves had the same photosynthetic rate as TM-1. However, application of high temperature induced stomatal closure and reduced photosynthesis more severely in im leaves than in TM-1. Comparative transcriptomic analyses consistently showed differential expressions of genes involved in abiotic stress responses and photosynthesis in im leaves. These results suggested that the genetic mutation of the im plant may cause hypersensitivity to high temperature stress and reduced abiotic stress tolerance. Our findings provided insight into how abiotic stress triggered and jointly amplified the effect of the mutation in the im plants.