Roles of glycine betaine and proline in improving plant abiotic stress resistance

Mechanisms of membrane toxicity of hydrocarbons.

When exposed to stressful conditions, plants accumulate an array of metabolites, particularly amino acids. Amino acids have traditionally been considered as precursors to and constituents of proteins, and play an important role in plant metabolism and development. A large body of data suggests a positive correlation between proline accumulation and plant stress. Proline, an amino acid, plays a highly beneficial role in plants exposed to various stress conditions. Besides acting as an excellent osmolyte, proline plays three major roles during stress, i.e., as a metal chelator, an antioxidative defense molecule and a signaling molecule. Review of the literature indicates that a stressful environment results in an overproduction of proline in plants which in turn imparts stress tolerance by maintaining cell turgor or osmotic balance; stabilizing membranes thereby preventing electrolyte leakage; and bringing concentrations of reactive oxygen species (ROS) within normal ranges, thus preventing oxidative burst ...

https://www.tandfonline.com/doi/pdf/10.4161/psb.21949

Role of proline under changing environments: a review.

Infertility and problems of impaired fecundity have been a concern through ages and is also a significant clinical problem today, which affects 8-12% of couples worldwide. Of all infertility cases, approximately 40-50% is due to "male factor" infertility and as many as 2% of all men will exhibit suboptimal sperm parameters. It may be one or a combination of low sperm concentration, poor sperm motility, or abnormal morphology. The rates of infertility in less industrialized nations are markedly higher and infectious diseases are responsible for a greater proportion of infertility. The present literature will help in knowing the trends of male factor infertility in developing nations like India and to find out in future, various factors that may be responsible for male infertility.

Trends of male factor infertility, an important cause of infertility: A review of literature.

Soil salinity is a major environmental constraint to crop productivity worldwide. The “biological” approach to this problem focuses on the management, exploitation, or development of plants able to thrive on salt‐affected soils. This chapter reviews strategies by which plants can be enabled to grow on saline soils. The first strategy is to prime seeds before planting by treating them with inorganic or organic chemicals and/or with high or low temperatures. The second strategy involves exogenous application of organic chemicals, such as glycine betaine, proline, or plant growth regulators, or inorganic chemicals to plants under salinity stress. Considerable improvements in growth and yield have been reported in a number of crops using these approaches. The third strategy is to employ selection and breeding. Major efforts have been made to develop salt‐tolerant lines or cultivars of crops using conventional plant breeding. However, the complexity of the tolerance mechanisms, lack of selection criteria, and variation in responses of plants at different developmental stages have resulted in only limited success. The emphases for developing salt‐tolerant lines/cultivars are now on marker‐assisted breeding and genetic transformation. The development of salt‐tolerant transgenic plants is still at an early stage but may become increasingly more effective as better knowledge of the complex mechanisms involved in plant salt tolerance is acquired. Furthermore, the rapid expansion in knowledge on genomics and proteomics will undoubtedly accelerate the transgenic and molecular breeding approaches However, to date, there are few conclusive reports indicating successful performance of transgenic cultivars under natural stressful environments.

Some Prospective Strategies for Improving Crop Salt Tolerance

The counteraction of exogenous L-proline at different concentrations with salinity (100 mM NaCl at sublethal concentration) were observed on germinating rice. Supplemented 30 mM L-proline was shown to be the most effective; at higher concentration it reduced seedling growth and K+/Na+ ratio. Thus 30 mM L-proline can alleviate the salinity stress in rice seedlings.

Counteraction of exogenous L-proline with NaCl in salt-sensitive cultivar of rice

https://www.clevelandclinic.org/reproductiveresearchcenter/docs/agradoc305.pdf

Semen quality and age-specific changes: a study between two decades on 3,729 male partners of couples with normal sperm count and attending an andrology laboratory for infertility-related problems in an Indian city.

Growth, chlorophyll a content, nitrogen-fixing ability, and certain metabolic activities of Nostoc muscorum: effect of methylparathion and benthiocarb.

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The effect of dietary protein levels on the proteolytic activity in the intestines of the air-breathing fish, Clarias batrachus (Linn.) has been studied




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Activity of proteolytic enzymes increased significantly in fishes maintained with a 50% protein diet from those maintained with a 25% protein diet; still higher dietary protein percentage showed no further stimulation of enzyme activity.




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In a study on the determination of sub-cellular localisation, it has been found that protease activity is more prominent in lysosomes than in other organelles of the cell.




4.

A sixty fold purification of alkaline protease from the intestine of Clarias batrachus has been achieved by ion exchange chromatography on DEAE cellulose which has been further checked by polyacrylamide gel electrophoresis.

Studies on intestinal protease: Isolation, purification and effect of dietary proteins on alkaline protease activity of the air-breathing fish, Clarias batrachus (Linn.)

The effect of NaCl at sublethal concentration was observed on germinating seeds of salt-sensitive and -resistant rice cultivars with respect to the level of proline regulatory enzymes and the growth of seedlings on different days of early germination period. The two enzymes of proline biosynthesis and catabolism, Δ-pyrroline-5-carboxylate reductase and L-proline dehydrogenase, were taken into consideration to observe the effects of 100 mM NaCl on their activities in both rice cultivars. The activity of Δ-pyrroline-5-carboxylate reductase in salt-resistant cultivar was increased twice after 5 d in 100 mM NaCl. Simultaneously, the activity of L-proline dehydrogenase was decreased significantly. High activities of Δ-pyrroline-5-carboxylate reductase may be regarded as a biological marker for screening the sensitive and resistant cultivars of rice seed under NaCl-salinity.

S. K. Banerjee

Papers

Counteraction of exogenous L-proline with NaCl in salt-sensitive cultivar of rice

Semen quality and age-specific changes: a study between two decades on 3,729 male partners of couples with normal sperm count and attending an andrology laboratory for infertility-related problems in an Indian city.

Growth, chlorophyll a content, nitrogen-fixing ability, and certain metabolic activities of Nostoc muscorum: effect of methylparathion and benthiocarb.

Studies on intestinal protease: Isolation, purification and effect of dietary proteins on alkaline protease activity of the air-breathing fish, Clarias batrachus (Linn.)

Effect of nacl- salinity on metabolism of proline in salt- sensitive and salt- resistant cultivars of rice