Ice-Binding Proteins in Plants

Abstract

Sub-zero temperatures put plants at risk of damage associated with the formation of ice crystals in the apoplast. Some freeze-tolerant plants mitigate this risk by expressing ice-binding proteins (IBPs), that adsorb to ice crystals and modify their growth. IBPs are found across several biological kingdoms, with their ice-binding activity and function uniquely suited to the lifestyle they have evolved to protect, be it in fishes, insects or plants. While IBPs from freeze-avoidant species significantly depress the freezing point, plant IBPs typically have a reduced ability to lower the freezing temperature. Nevertheless, they have a superior ability to inhibit the recrystallization of formed ice. This latter activity prevents ice crystals from growing larger at temperatures close to melting. Attempts to engineer frost-hardy plants by the controlled transfer of IBPs from freeze-avoiding fish and insects have been largely unsuccessful. In contrast, the expression of recombinant IBP sequences from freeze-tolerant plants significantly reduced electrolyte leakage and enhanced freezing survival in freeze-sensitive plants. These promising results have spurred additional investigations into plant IBP localization and post-translational modifications, as well as a re-evaluation of IBPs as part of the anti-stress and anti-pathogen axis of freeze-tolerant plants. Here we present an overview of plant freezing stress and adaptation mechanisms and discuss the potential utility of IBPs for the generation of freeze-tolerant crops.

Effects of nitrogen application rate on productivity, nutritive value and winter tolerance of timothy and meadow fescue cultivars

“…N storages, especially vegetative storage proteins, have been shown to contribute positively to the regrowth ability of grasses (Volenec, Ourry, & Joern, 1996). It is also possible that other mechanisms that improve cold acclimation and winter tolerance, for example synthesis of ice-binding proteins or modifications of the plasma membrane, are affected by N fertilizer application (Bredow & Walker, 2017). N application levels up to 60 kg N ha -1 for the third cut therefore probably improved the growth potential of grasses in spring without causing winter damage.…”

Ice‐binding proteins and the ‘domain of unknown function’ 3494 family

“…Ice‐binding proteins were first discovered in fishes in the late 1960s and described as antifreeze proteins (AFPs) because they functioned to depress the freezing point of biological fluids . Since then, IBPs performing a variety of biological roles have been isolated and characterized from many different organisms, including fishes, insects, plants, bacteria, fungi and algae . In higher eukaryotes, two IBP functions that counteract freezing damage are freeze avoidance and freeze tolerance.…”

Single‐step purification and characterization of antifreeze proteins from leaf and berry of a freeze‐tolerant shrub seabuckthorn (Hippophae rhamnoides)

“…The protein triggers plant defense system including the hypersensitive response and protect the plant by restricting the growth of avirulence protein containing pathogens. The protein is also induced by salicylic acid, light, and wounding thereby suggesting its putative role in both biotic and abiotic responses …”

“…The protein triggers plant defense system including the hypersensitive response and protect the plant by restricting the growth of avirulence protein containing pathogens. The protein is also induced by salicylic acid, light, and wounding thereby suggesting its putative role in both biotic and abiotic responses [16] Further, leaf AFP (HrL1) identified as transmembrane protein acts as osmo-regulated transport systems, sensor kinases, and mechanosensitive channel proteins which helps in activation of the signalling cascade during stress responses [17]. Interestingly, another leaf AFP (HrL2) showed homology with low temperature induced 65 kDa protein isoform (72%) from D. carota known to be involved in abiotic stress responses including cold, drought, salt, abscisic acid and is generally expressed during leaf senescence.…”