Min Yu

Bio: Min Yu is an academic researcher from Foshan University. The author has contributed to research in topics: Medicine & Biology. The author has an hindex of 15, co-authored 43 publications receiving 468 citations.

Non-stomatal limitation of photosynthesis by soil salinity

Abstract: Soil salinity is a major threat to agricultural sustainability and a global food security. Until now, most research has concentrated around stomatal limitation to photosynthesis, while non-stomatal...

Reducing Cadmium Accumulation in Plants: Structure–Function Relations and Tissue-Specific Operation of Transporters in the Spotlight

Abstract: Cadmium (Cd) is present in many soils and, when entering the food chain, represents a major health threat to humans. Reducing Cd accumulation in plants is complicated by the fact that most known Cd transporters also operate in the transport of essential nutrients such as Zn, Fe, Mn, or Cu. This work summarizes the current knowledge of mechanisms mediating Cd uptake, radial transport, and translocation within the plant. It is concluded that real progress in the field may be only achieved if the transport of Cd and the above beneficial micronutrients is uncoupled, and we discuss the possible ways of achieving this goal. Accordingly, we suggest that the major focus of research in the field should be on the structure-function relations of various transporter isoforms and the functional assessment of their tissue-specific operation. Of specific importance are two tissues. The first one is a xylem parenchyma in plant roots; a major "controller" of Cd loading into the xylem and its transport to the shoot. The second one is a phloem tissue that operates in the last step of a metal transport. Another promising and currently underexplored avenue is to understand the role of non-selective cation channels in Cd uptake and reveal mechanisms of their regulation.

GABA operates upstream of H+-ATPase and improves salinity tolerance in Arabidopsis by enabling cytosolic K+ retention and Na+ exclusion.

Abstract: The non-protein amino acid γ-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to salinity. However, the physiological rationale for this elevation remains elusive. This study compared electrophysiological and whole-plant responses of salt-treated Arabidopsis mutants pop2-5 and gad1,2, which have different abilities to accumulate GABA. The pop2-5 mutant, which was able to overaccumulate GABA in its roots, showed a salt-tolerant phenotype. On the contrary, the gad1,2 mutant, lacking the ability to convert glutamate to GABA, showed oversensitivity to salinity. The greater salinity tolerance of the pop2-5 line was explained by: (i) the role of GABA in stress-induced activation of H+-ATPase, thus leading to better membrane potential maintenance and reduced stress-induced K+ leak from roots; (ii) reduced rates of net Na+ uptake; (iii) higher expression of SOS1 and NHX1 genes in the leaves, which contributed to reducing Na+ concentration in the cytoplasm by excluding Na+ to apoplast and sequestering Na+ in the vacuoles; (iv) a lower rate of H2O2 production and reduced reactive oxygen species-inducible K+ efflux from root epidermis; and (v) better K+ retention in the shoot associated with the lower expression level of GORK channels in plant leaves.

Cell Wall Pectin and its Methyl-esterification in Transition Zone Determine Al Resistance in Cultivars of Pea (Pisum sativum)

Abstract: The initial response of plants to aluminum (Al) is the inhibition of root elongation, while the transition zone is the most Al sensitive zone in the root apex, which may sense the presence of Al and regulate the responses of root to Al toxicity. In the present study, the effect of Al treatment (30 μM, 24 h) on root growth, Al accumulation, and properties of cell wall of two pea (Pisum sativum L.) cultivars, cv Onward (Al-resistant) and cv Sima (Al-sensitive), were studied to disclose whether the response of root transition zone to Al toxicity determines Al resistance in pea cultivars. The lower relative root elongation (RRE) and higher Al content were founded in cv Sima compared with cv Onward, which were related to Al-induced the increase of pectin in root segments of both cultivars. The increase of pectin is more prominent in Al-sensitive cultivar than in Al-resistant cultivar. Aluminum toxicity also induced the increase of pectin methylesterases (PME), which is 2.2 times in root transition zone in Al-sensitive cv Sima to that of Al resistant cv Onward, thus led to higher demethylesterified pectin content in root transition zone of Al-sensitive cv Sima. The higher demethylesterified pectin content in root transition zone resulted in more Al accumulation in the cell wall and cytosol in Al-sensitive cv Sima. Our results provide evidence that the increase of pectin content and PME activity under Al toxicity cooperates to determine Al sensitivity in root transition zone that confers Al resistance in cultivars of pea (Pisum sativum).

Mechanisms of Plant Responses and Adaptation to Soil Salinity.

Abstract: Soil salinity is a major environmental stress that restricts the growth and yield of crops. Understanding the physiological, metabolic, and biochemical responses of plants to salt stress and mining the salt tolerance-associated genetic resource in nature will be extremely important for us to cultivate salt-tolerant crops. In this review, we provide a comprehensive summary of the mechanisms of salt stress responses in plants, including salt stress-triggered physiological responses, oxidative stress, salt stress sensing and signaling pathways, organellar stress, ion homeostasis, hormonal and gene expression regulation, metabolic changes, as well as salt tolerance mechanisms in halophytes. Important questions regarding salt tolerance that need to be addressed in the future are discussed.

Boron deficiency-induced impairments of cellular functions in plants: a review

Abstract: The essentiality of B for growth and development of plants is well-known, but the primary functions of B still remain unknown. Evidence in the literature supports the idea that the major functions of B in growth and development of plants are based on its ability to form complexes with the compounds having cis-diol configurations. In this regard, the formation of B complexes with the constituents of cell walls and plasma membranes as well as with the phenolic compounds seems to be a decisive step affecting the physiological functions of B. Boron seems to be of crucial importance for the maintenance of structural integrity of plasma membranes. This function of B is mainly related to stabilisation of cell membranes by B association with membrane constituents. Possibly, B may also protect plasma membranes against peroxidative damage by toxic O2 species. In B-deficient plants, plasma membranes are highly leaky and lose their functional integrity. Under B-deficient conditions, substantial changes in ion fluxes and proton pumping activity of the plasma membranes were noted. Impairments in phenol metabolism and increases in levels of phenolics and polyphenoloxidase activity are typical indications of B deficiency, particularly in B deficiency-sensitive plant species, such as Helianthus annuus (sunflower). Enhanced oxidation of phenols is responsible for generation of reactive quinones which subsequently produce extremely toxic O2 species, thus resulting in the increased risk of a peroxidative damage to vital cell components such as membrane lipids and proteins. In B-deficient tissues, enhancement in levels of toxic O2 species may also occur as a result of impairments in photosynthesis and antioxidative defence systems. Recent evidence shows that the levels of ascorbic acid, non-protein SH-compounds (mainly glutathione) and glutathione reductase, the major defence systems of cells against toxic O2 species, are reduced in response to B deficiency. There is also increasing evidence that, in the heterocyst cells of cyanobacteria, B is involved in protection of nitrogenase activity against O2 damage.

Silicon Regulates Antioxidant Activities of Crop Plants under Abiotic-Induced Oxidative Stress: A Review

Abstract: Silicon (Si) is the second most abundant element in soil, where its availability to plants can exhilarate to 10% of total dry weight of the plant. Si accumulation/transport occurs in the upward direction, and has been identified in several crop plants. Si application has been known to ameliorate plant growth and development during normal and stressful conditions over past two-decades. During abiotic (salinity, drought, thermal, and heavy metal etc) stress, one of the immediate responses by plant is the generation of reactive oxygen species (ROS), such as singlet oxygen (1O2), superoxide (O2−), hydrogen peroxide (H2O2), and hydroxyl radicals (OH), which cause severe damage to the cell structure, organelles, and functions. To alleviate and repair this damage, plants have developed a complex antioxidant system to maintain homeostasis through non-enzymatic (carotenoids, tocopherols, ascorbate, and glutathione) and enzymatic antioxidants [superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX)]. To this end, the exogenous application of Si has been found to induce stress tolerance by regulating the generation of ROS, reducing electrolytic leakage and malondialdehyde (MDA) contents, and immobilizing and reducing the uptake of toxic ions like Na, under stressful conditions. However, the interaction of Si and plant antioxidant enzyme system remains poorly understood, and further in-depth analyses at the transcriptomic level are needed to understand the mechanisms responsible for the Si-mediated regulation of stress responses.