Chitooligosaccharides enhance cold tolerance by repairing photodamaged PS II in rice

Abstract

Chitooligosaccharides (COS) are multi-functional foods and nutrients and environmentally friendly biological abiotic-resistance inducing agents for plants. In the current study, the effects and possible mechanisms of COS on improving the cold resistance of rice (II YOU 1259) seedlings were investigated. Compared with the control, a COS pre-soaking treatment enhanced photosynthesis, reduced oxidation damage and led to accumulation of more osmotic regulation substances under chilling treatment. In addition, a novel Deg/HtrA family serine endopeptidase (DegQ) gene, related to COS enhanced rice cold resistance, was identified. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that transcription of DegQ and psbA (D1 protein encoding gene) were up-regulated in a time-dependent manner by COS treatment under cold stress. With increasing expression of the D1 protein, chlorophyll b content was enhanced correspondingly. The current results suggest that COS could enhance cold stress tolerance of rice by repairing the photodamaged photosystem II, altering osmotic regulation and reducing oxidation damage.

Purification and Characterization of a Novel Endolytic Alginate Lyase from Microbulbifer sp. SH-1 and Its Agricultural Application

“…These results are consistent with the previous research that exogenous chitooligosaccharides (COS) treatment increased plant height and fresh weight in rice, and foliar-applied oligocarrageenan improved photosynthetic parameters in peppermint under chilling stress [51,52]. A recent study reports that pretreatment with COS can induce the expression of PSII D1 protein-encoding genes, indicating it plays an important role in the repairing process of photo damaged PSII [28]. The alleviating effect of alginate oligosaccharides on the cold stress-induced damage to photosystem II may due to the same mechanism.…”

“…The low temperature is one of the major adverse environmental stresses posing damage to horticultural crops and causing huge yield loss [28]. The application of functional chemical compounds could be a vital way to enhance plant abiotic resistance.…”

Chitin and Chitosan Fragments Responsible for Plant Elicitor and Growth Stimulator

“…In recent years, chitosan and its fragments have likewise attracted increasing attention as a plant protection agent, effectively inducing plants against abiotic stress, such as water deficit, 52,53 salinity, 6 heavy metal toxicity, 54 and chilling stress. 55 These unfavorable environmental conditions commonly cause many deleterious effects on plant growth, which mainly include the production of ROS, lipid peroxidation of membrane, inhibition of nutrients, and water uptake due to low external osmotic potential or the toxic effect resulting from higher ions accumulation. Corresponding to these physical changes in plants under stress conditions, antioxidant enzymes, malondialdehyde (MDA) concentration, proline content, and photosynthetic parameters were generally applied to evaluate the protective effect of chitosan on plants against abiotic stress.…”

“…In recent years, chitosan and its fragments have likewise attracted increasing attention as a plant protection agent, effectively inducing plants against abiotic stress, such as water deficit, , salinity, heavy metal toxicity, and chilling stress . These unfavorable environmental conditions commonly cause many deleterious effects on plant growth, which mainly include the production of ROS, lipid peroxidation of membrane, inhibition of nutrients, and water uptake due to low external osmotic potential or the toxic effect resulting from higher ions accumulation.…”

Effect of Freezing on Photosystem II and Assessment of Freezing Tolerance of Tea Cultivar

“…There was a study showing that the gene WHY1 binding to the upstream region of psbA enhanced the cold tolerance of tomato by increasing the de novo synthesis of D1 protein and maintaining the function of PSII in chloroplasts [45]. The application of chitooligosaccharides could enhance cold tolerance of rice by repairing the photodamaged PSII through upregulating psbA [46]. This technique is worth trying in the high latitude tea growing areas with severely freezing winter.…”