IMR Press / FBL / Volume 29 / Issue 2 / DOI: 10.31083/j.fbl2902060
Open Access Original Research
Natural Albino Mutant of Daylily (Hemerocallis spp.) Reveals a Link between Drought Sensitivity and Photosynthetic Pigments Metabolism
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1 School of Ecological Technology and Engineering, Shanghai Institute of Technology (SIT), 201418 Shanghai, China
2 Shanghai Key Laboratory of Protected Horticultural Technology, Forestry and Fruit Tree Research Institute, Shanghai Academy of Agricultural Sciences (SAAS), 201403 Shanghai, China
3 Department of Plant Physiology, Institute for Biological Research “Siniša Stanković” - National Institute of Republic of Serbia, University of Belgrade, 11060 Belgrade, Serbia
*Correspondence: (Di-an Ni)
Front. Biosci. (Landmark Ed) 2024, 29(2), 60;
Submitted: 23 June 2023 | Revised: 8 November 2023 | Accepted: 17 November 2023 | Published: 6 February 2024
Copyright: © 2024 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Background: Mutant analysis remains one of the main genetic tools for characterising unclarified gene functions in plants, especially in non-model plants. Daylily (Hemerocallis spp.) is a popular perennial ornamental plant grown worldwide. Analysis of daylily mutants can enhance understanding of genes regulating the albino phenotype and improve the cultivar quality of daylily. Methods: The natural albino mutant (Alb-/-) was isolated by screening a self-pollinated progeny of daylily cultivar ‘black-eyed stella’. Transmission electron microscopy was used in analysing the structure of plastids between mutant and wild-type seedlings. The content of chlorophyll, carotenoids and chlorophyll precursors in plants was measured by ultraviolet spectrophotometry. RNA sequencing and physiological measurements were performed to explore the association between drought tolerance and mutation. Results: All the seedlings of the daylily albino mutants died spontaneously within fifteen days after germination when grown in soil. The carotenoid and chlorophyll content in the leaves of the mutant plants significantly decreased compared with those of the wild-type control. The mutant plants displayed stunted growth, and their leaves were white or light yellow in color. Abnormal plastids such as those showing endomembrane vesiculation and lacking stacking were discovered in the leaves of mutant plants. Furthermore, genetic analysis revealed that a single recessive nuclear gene mutation led to the albino trait, RNA sequencing and real-time quantitative PCR validation showed extensive differences in gene expression between the mutant plants and the wild-type control, and most of the genes related to chlorophyll metabolism were down-regulated, with foldchange ranging from 0.20–0.49. Additionally, the surviving homozygous plants (Alb+/+), which do not contain this mutation, were also isolated by analysing the phenotype of their self-pollinated progeny. The net photosynthesis rate and light saturation point of Alb+/+ were higher than those of heterozygous (Alb+/-) plants. Additionally, the Alb+/+ plants were more tolerant to drought conditions than the Alb+/- plants, suggesting that a heterozygous Alb- mutation is sufficient to negatively affect photosynthetic efficiency and drought tolerance. Conclusions: The albino mutation negatively affects photosynthetic efficiency and drought tolerance, and homozygous mutation is required for the characteristic albino phenotype. This work highlights the link between albino mutation, photosynthetic pigment metabolism and drought sensitivity in daylily.

daylily (Hemerocallis spp.)
drought tolerance
natural albino mutant
light saturation point
RNA sequencing
23010504800/Shanghai Municipal Commission of Science and Technology, capacity building project for local universities
2022144/China Education Association for International Exchange
451-03-47/2023-01/200007/Ministry of Science, Technological Development and Innovation of Republic of Serbia
Fig. 1.
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