Cold stress tolerance of the intertidal red alga Neoporphyra haitanensis

Abstract

Background Red algae Porphyra sensu lato grow naturally in the unfavorable intertidal environment, in which they are exposed to substantial temperature fluctuations. The strategies of Porphyra to tolerate cold stress are poorly understood. Results Herein, investigations revealed that chilling and freezing induced alterations in the physiological properties, gene transcriptional profiles and metabolite levels in the economically important red algae species, Neoporphyra haitanensis. Control samples (kept at 20 °C) were compared to chilled thalli (10 and 4 °C) and to thalli under − 4 °C conditions. Chilling stress did not affect the health or photosynthetic efficiency of gametophytes, but freezing conditions resulted in the arrest of growth, death of some cells and a decrease in photosynthetic activity as calculated by Fv/Fm. Transcriptome sequencing analysis revealed that the photosynthetic system was down-regulated along with genes associated with carbon fixation and primary metabolic biosynthesis. Adaptive mechanisms included an increase in unsaturated fatty acids levels to improve membrane fluidity, an increase in floridoside and isofloridoside content to enhance osmotic resistance, and an elevation in levels of some resistance-associated phytohormones (abscisic acid, salicylic acid, and methyl jasmonic acid). These physiochemical alterations occurred together with the upregulation of ribosome biogenesis. Conclusions N. haitanensis adopts multiple protective mechanisms to maintain homeostasis of cellular physiology in tolerance to cold stress.

Determination and quantification of two regulatory phytohormones extracted from Sargassum muticum and Gracilaria corticata seaweeds in the south of Iran

“…The findings also showed that, environmental factors such as temperature and salinity have a limiting effect on algal biomass in the presence of growth inhibitors (ABA) and growth stimulants (IAA). Zhu et al (2022) found that, the IAA level accompanied by some other growth regulatory phytohormones in red algae, Neoporphyra haitanensis, decrease significantly upon exposing to cold temperature, representing that algae could adjust to the cold stress by their regulating phytohormones and slowing down growth subsequently. Though, some other phytohormones related to stress resistance, such as ABA, were expressively increase at low temperatures.…”

Physiological properties of Neoporphyra haitanensis conchocelis in response to different temperature

“…Higher content of inositol was observed in high temperature (28°C), which suggested that inositol may function as a compatible solute for protection against high temperature (Tan et al, 2013). The accumulation of floridoside and isofloridoside can effectively stabilize the macromolecular substances and membrane structures in cells at low and high temperatures, preventing them from being damaged by cold or high stress (Liang et al, 2021; Zhu et al, 2022).…”

“…Therefore, Pyropia must have already developed a variety of highly effective strategies and mechanisms to overcome these environmental stresses. Most physiological studies of Pyropia have concentrated on responses to temperature of thalli (Chen et al, 2016; Luo et al, 2014; Wang et al, 2018; Wu et al, 2022; Zhu et al, 2022). The growth rates, photosynthetic performances, and photosynthetic pigment concentrations increased with increasing temperature, but decreased when the temperature increased at the thermal threshold of Pyropia haitanensis (24°C) (Wu et al, 2022).…”

“…Low-molecular-weight carbohydrates are mainly involved as osmotic regulators in plant cell responses to stress (Keunen et al, 2013). Floridoside and isofloridoside increased under cold stress to enhance osmotic resistance in Neoporphyra haitanensis (Zhu et al, 2022). Myo-inositol and sorbitol were higher in the 5% relative water content group than the hydration group (Wang et al, 2022).…”

A novel and high‐throughput approach to assess photosynthetic thermal tolerance of kelp using chlorophyll α fluorometry

“…Similarly, cold snaps are also predicted to increase, and may have large impacts on intertidal species in polar and subpolar systems (Becker et al 2009, Scrosati andEllrich 2018). Cold snaps during the shoulder seasons when frosts and sea ice can occur earlier or later in the season can result in extracellular ice formation leading to cell death and inhibition to growth and development (Davison et al 1989, Zhu et al 2022. It is, therefore, necessary to investigate seaweed tolerance to both extreme heat and cold, to understand global patterns and drivers of seaweed losses and to be able to predict the future vulnerability of these important habitats.…”