Molecular mechanisms of stress resistance in sorghum: Implications for crop improvement strategies

Abiotic stresses, such as drought, salt, extreme temperatures, and heavy metal pollution, are the main environmental factors that limit crop growth and yield. Sorghum, a C4 grass plant with high photosynthetic efficiency, can grow in adverse environmental conditions due to its excellent stress resistance characteristics. Therefore, unraveling the stress-resistance mechanism of sorghum could provide a theoretical basis for developing and cultivating various stress-resistant crops. This understanding could also help to create a conducive environment for using marginal soil in agriculture and ensuring food security. In this review, we discuss the adaptation mechanisms of sorghum under drought, salinity, temperature, and soil heavy metal stresses, the specific response to stress, the screening of sorghum-resistant germplasm, and the identification and functional analysis of the relevant genes and quantitative trait loci(QTL). In addition, we discuss the application potential of different stress-tolerant sorghum germplasms reported to date and emphasize the feasibility and potential use in developing and promoting highly stress-tolerant sorghum in marginal soil.

Effects of silicon content on microstructure and stress corrosion cracking resistance of 7050 aluminum alloy

Evolution of microstructure and stress corrosion cracking （SCC） susceptibility of 7050 aluminum alloy with 0.094%, 0.134% and 0.261% Si （mass fraction） in T7651 condition have been investigated. The results show that the area fraction of Mg2Si increases from 0.16% to 1,48% and the size becomes coarser, while the area fraction of the other coarse phases including Al2CuMg, Mg（Al,Cu,Zn）2 and A17Cu2Fe decreases from 2.42% to 0.78% with Si content increasing from 0.094% to 0.261%. The tensile strength and elongation of 7050-T7651 alloys is decreased with the increase of Si content by slow strain rate test （SSRT） in ambient air. However, electrical conductivity is improved and SCC susceptibility is reduced with the increase of Si content by SSRT in corrosion environment with 3.5% NaCl solution.

Upregulation of the glycine-rich protein-encoding gene GhGRPL enhances plant tolerance to abiotic and biotic stressors by promoting secondary cell wall development

Abiotic and biotic stressors adversely affect plant survival,biomass generation,and crop yields.As the global availability of arable land declines and the impacts of global warming intensify,such stressors may have increasingly pronounced effects on agricultural productivity.Currently,researchers face the overarching challenge of comprehensively enhancing plant resilience to abiotic and biotic stressors.The secondary cell wall plays a crucial role in bolstering the stress resistance of plants.To increase plant resistance to stress through genetic manipulation of the secondary cell wall,we cloned a cell wall protein designated glycine-rich protein-like(GhGRPL)from cotton fibers,and found that it is specifically expressed during the period of secondary cell wall biosynthesis.Notably,this protein differs from its Arabidopsis homolog,AtGRP,since its glycine-rich domain is deficient in glycine residues.GhGRPL is involved in secondary cell wall deposition.Upregulation of GhGRPL enhances lignin accumulation and,consequently,the thickness of the secondary cell walls,thereby increasing the plant’s resistance to abiotic stressors,such as drought and salinity,and biotic threats,including Verticillium dahliae infection.Conversely,interference with GhGRPL expression in cotton reduces lignin accumulation and compromises that resistance.Taken together,our findings elucidate the role of GhGRPL in regulating secondary cell wall development through its influence on lignin deposition,which,in turn,reinforces cell wall robustness and impermeability.These findings highlight the promising near-future prospect of adopting GhGRPL as a viable,effective approach for enhancing plant resilience to abiotic and biotic stress factors.

Research Progress and Identification Method of Apple Stress Resistance

In the research, changes of apple chemistry, and molecule, under stresses, are n terms of morphology, physiology, bio- illustrated and research and identifica- tion methods of apple resistance are explored involving drought-resistance, flood-re- sistance, salt-stress resistance, cold-hardiness and heat-resistance. In addition prospects of apple resistance research are proposed, as well.

Study on Germplasm Resources of Peach Cultivars

[Objectives]To study the germplasm resources of excellent peach cultivars.[Methods]Five peach cultivars were introduced,in-cluding‘Jinxiu’peach,‘Jinxiang’peach,‘Chunxiao’peach,‘Hujingmilu’peach and‘018 nectarine’peach.Then,these five cultivars were used to study the biological characteristics of peach trees,namely,as phenology,fruit quality,heat resistance,cold resistance and other resistance.[Results]Five cultivars of peach plants grew fast and robust,among which‘018 nectarine’had very crisp fruit,‘Jinxiu’,‘Jinxiang’,‘Chunxiao’and‘Hujingmilu’had very sweet fruitꎻthe peach trees of these five cultivars have good water resistance,heat resist-ance and cold resistance.[Conclusions]The results of this study can not only provide a reference for the introduction of peach trees,but also provide a practical basis for the large-scale planting of peach trees.

Immune response,stress resistance and bacterial challenge in juvenile rainbow trouts Oncorhynchus mykiss fed diets containing chitosan-oligosaccharides

Effects of dietary supplementation of chitosan-oligosaccharides （COS） on the growth performance, immune response, stress resistance, and disease resistance of juvenile rainbow trout Oncorhynchus mykiss were studied. Four experimental diets containing 0, 20, 40, or 60 mg/kg COS （COSO, COS20, COS40, and COS60, respectively） were fed to juvenile rainbow trout （initial weight = 5.2 ± 0.3 g） for 8 weeks. By the end of the feeding trial, representative groups of fish from each dietary treatment were challenged with stressor （30 see air exposure） and pathogen exposure （intraperitoneal injection with Aeromonas hydrophila ）. Results showed that supplementation of COS in diets did not affect production performance and body composition of rainbow trout. However, fish fed the COS40 diet demonstrated improved phagocytic activities, respiratory burst activities and decreased serum cortisol level. Additionally, survival following A. hydrophila challenge was significant higher among fish fed the COS-supplemented feeds, although there was no difference based on the level of supplementation. The present study suggests that COS can be used as an immuno-stimulant in rainbow trout feeds

Comparative Study on the Cold Resistance of Four Cherry Cultivars under Chilling Stress

[Objective] The present study was conducted to evaluate the cold resis-tance of four cherry cultivars under different chil ing stresses. [Method] Four cultivars of Cerasus, Early-mahapphala, Red light, Lapins and Kashgar Kukan were selected as the experimental materials, and the changes of the relative electric conductivity （REC）, proline （PRO） content, malondialdehyde （MDA） content, superoxide dismu-tase （SOD） activity and peroxidase （POD） activity of dormant branches of the four cherry cultivars under low temperature stress were investigated. [Result] The REC of the four cherry cultivars was Kashgar kukan 〉 Red light 〉 Early-mahapphala 〉Lapins, while the MDA content was Kashgar kukan 〉 Early-mahapphala 〉 Red light 〉Lapins, both showed a rising trend in the four cultivars with the aggravating of the low temperature stress. The PRO content, POD and SOD activities of al cultivars were precisely contrary to their REC and MDA content, as al of them exhibited a sequence as Lapins 〉 Red light 〉 Early-mahapphala 〉 Kashgar kukan in al culti-vars, and got a trend of first rising and then declining. [Conclusion] Therefore, our final evaluation of cold resistance of the four cherry cultivars was Lapins 〉 Red light 〉 Early-mahapphala 〉 Kashgar kukan.

Effects of arbuscular mycorrhizal fungi on the drought resistance of the mining area repair plant Sainfoin

To solve the problem of lack of water in arid areas and barren soil in the process of ecological restoration, the growth and drought resistance of Sainfoin （Onobrychis vidifolia Scop.） was studied by inoculation of AMF （arbuscular rnycorrhizal fungi）, under drought stress. The results show that the inoculation of AMF can significantly improve the growth and mycorrhizal infection rate of Sainfoin and accelerate the absorption of water and nutrients by the roots compared with uninoculated plants. On the 40th day under drought stress, the relative water content, total nitrogen and total phosphorus content of the leaves of inoculated plants increased by 7.27%, 4.21% and 2.40%, respectively, the osmotic adjustment property in plant cells was improved, the protective enzyme system was improved and membrane lipid peroxida- tion was reduced. The inoculation of AMF can slow down the damage from drought, improve the drought resistance of Sainfoin, and will be of great significance to the ecologic restoration in arid areas.

Progress of Research on Stress Resistance of Rice in China

Progress of rice resistance research in China was reviewed in the study based on exploitation of wild rice, breeding of hybrid rice, new resistant rice variety, stress resistance gene, relation between hormone and rice resistance, effects of Si and Ca on yield increase, providing reference for research of rice yield improvement.

Theoretical analysis of influencing factors on resistance in the process of gas migration in coal seams

Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.

Hypoxic Preconditioning Eliminates Differences in the Innate Resistance of Rats to Severe Hypoxia

Hypoxic preconditioning is able to increase the body’s resistance to hypoxic/ischemic stress. Understanding how to apply the hypoxic response to initiate the protective mechanism of ischemic preconditioning is a high priority. However, the relationship between innate resistance to hypoxic stress and preconditioning efficiency of moderate hypoxia has been poorly studied. In our work, the efficiency of single moderate hypobaric hypoxia (HBH) for resistance to severe hypobaric hypoxia (SHBH) was studied on intact rats and those pre-tested under SHBH with low, intermediate and high resistance to hypoxia. HBH has a significant preconditioning action on the resistance to hypoxia over a wide range from 270 to 1464 s (4.5 to 24.5 min) and at the same time eliminates the differences in the endurance under SHBH between all rat groups. It is concluded that 1) HBH preconditioning efficiency does not depend on an innate resistance to SHBH and prior hypoxic experience of rats;and 2) the pretesting to severe hypoxia has no value for predicting the hypoxic preconditioning efficiency and study of adaptive mechanisms.

Integration of animal behaviors under stresses with different time courses

We used animal models of ＂forced swim stress＂ and ＂chronic unpredictable stress＂, and tried to reveal whether a passive coping style of high flotation behavior in forced swim stress predicts an- hedonia behavior after chronic unpredictable stress, and whether the dopamine system regulates floating and anhedonia behaviors. Our results confirmed that depression-prone rats use ＂floating behavior＂ as a coping strategy in forced swim stress and more readily suffer from anhedonia during chronic unpredictable stress. Intraperitoneal injection or nucleus accumbens microin- jection of the dopamine 2/3 receptor subtype agonist ropinirole reduced floating behaviors in depression-prone animals, but increased sucrose preference in rats showing anhedonia. These data indicate that floating behavior is a defensive mode that is preferred by susceptible individ- uals under conditions of acute stress. Simultaneously, these animals more readily experienced anhedonia under long-term stress; that is, they were more readily affected by depression. Our results suggest that dopamine 2/3 receptor subtypes in the nucleus accumbens play an important role in floating behaviors and anhedonia.

The sex peptide receptor in the Asian gypsy moth,Lymantria dispar,is involved in development and stress resistance

The G protein-coupled receptor(GPCR)regulates downstream genes by binding to a heterotrimeric G protein.However,the function of sex peptide receptor(SPR)in lepidopteran species is mostly unknown.Understanding the physiological functions of SPR in insects is essential for exploring new insecticidal targets.In the present study,the functions of an SPR in Lymantria dispar(Asian gypsy moth;LdSPR)were investigated.The expression of LdSPR was the highest in the 6 th instar larval stage,and there was a large difference in expression between male and female adults.After LdSPR gene silencing,L.dispar larvae showed increased sensitivity to high temperature,starvation,and oxidative stress,indicating that LdSPR enhances stress resistance.These results enrich our knowledge of the function of the insect SPRs,which will lead to a better understanding of other insect GPCR family members and the identification of new targets for the development of environmentally friendly pesticides.

Osmotic Stress Resistance of Transgenic Tobacco Expressed Soybean Lysine-rich Protein Gene

PM2 gene （accession number： M80664） with high lysine content from soybean （Glycine max） was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on the high level of 18.22%. Protein encoded by PM＇2 also belonged to the family of late embryogenesis abundant （LEA） proteins, which was considered that it had a strong relation with the abiotic stress resistance. In this experiment, PM2 gene was obtained from dry soybean seeds by RT-PCR, plant expression vector pEMTPM2 was constructed, and then transformed into tobacco by using agrobacterium-mediated method. Eight salt and drought tolerant lines were obtained from 31 differentiated lines. Real-time PCR showed that PM2 gene overexpressed in all four PCR positive lines with the osmotic stress resistance. These results confirmed that the overexpression of PM2 gene enhanced the osmotic stress resistance of transgenic tobacco.

Application of Molecular Marker Technologies in Stress Resistance Breeding of Rapeseed

Rapeseed is the largest source of China's edible vegetable oil and plays a pivotal role in China's edible oil market.With global warming and frequent occurrence of various extreme climates,traditional hybrid breeding has been unable to meet the production requirements for rape yield and stress resistance.In recent years,the rapid development and maturity of molecular marker technologies have opened up new ways for stress resistance breeding in rape.This article mainly discusses several types of molecular marker technologies commonly used in rapeseed breeding,such as RFLP,SSR,and SNP,the advantages of molecular marker technologies over conventional breeding and other genetic marker technologies,as well as the application of molecular marker technologies in rapeseed disease resistance,drought resistance,cold resistance and lodging resistance breeding,the current problems and development prospects in breeding.

Protein changes in rice seedlings during the enhancement of chilling resistance by different stress pretreatment

The changes of proteins in the rice (Oryzasativa L.) Tesanai 2 seedling under salt (NaCl,4 g/L), heat shock (42℃, 3h ), and cold(14℃, 3d ) pretreatments were compared toexplore the mechanism of the cross adaptationto different environmental stresses. The chill-ing resistance of rice seedling after 1℃, 150pmol·msPFD(photo flux density) for 2d was enhanced distinctly by salt, heat shock,

Pancreatic Enzymes Activity under the Conditions of Acute Stress and Melanin Administration Depending on the Stress Resistance

Total proteolytic, antitrypsic, amylase and lypolytic activity was studied on animals subjected to acute stress simulation. Acute stress results in the development of imbalance of protease inhibitors potential as well as in the increase of amylase and lipase activity in the pancreas of the rats. Prior melanin administration in acute stress leads to a decrease in the activity of amylase and lipase, and an increase of total activity of protease inhibitors, that demonstrates stress-protective melanin effect produced on the pancreas.

Relationship between changes of endogenous ABA level and resistance in hybrid rice under temperature stress

We studied the relationship between endogenous ABA and resistance to temperature stress in seedlings of hybrid rice. The hybrid rice Combinations Shanyou 63, Shanyou 287, Weiyou 63, and Weiyou 287 were treated under 2℃ and 42℃ respectively for 48 h. Endogenous ABA concentrations were obtained by gas chromatography with electron capture detector (GC-ECD) and a nickel labelled external standard. Leakage of electrolytes were determined. At optimal temperature (27℃), there was difference between the level of endogenous ABA and the leakage of electrolytes in hybrid rice combinations, which attributed to genetic difference. ABA level in Weiyou system was higher than that in Shanyou, and there were distinctions between Shanyou system itself (see table). At 2℃, the ABA content of rice seedling was increased. ABA level of Weiyou system maintained higher than Shanyou system at 27℃. The leakage quantities of

Study on Adaptability of Introduced Pear Varieties

[Objectives]To study the adaptability of introduced pear.[Methods]Five pear varieties,"Aidang"pear,"Taiwan Zaomi"pear,"Cuiguan"pear,"Tianjin Yali"pear and"Zaosheng Xinshui"pear,were introduced.Then,using these five varieties,the phenology of pear trees,various characters of fruit,stress resistance(heat tolerance and cold tolerance)of varieties were studied.[Results]The plants of 5 varieties of pear trees grew fast and were robust;in late March,it went into the flowering period;"Aidang"pear fruit had a certain number of stone cells;"Taiwan Zaomi"pear had the highest sweetness;"Cuiguan"pear had the largest fruit;these five varieties of pear trees had good water resistance,heat resistance and cold resistance.[Conclusions]This study can provide a reference for the introduction of pear trees,and can also provide a practical basis for the large-scale planting of pear trees.

Experimental Research on Pomegranate Varieties

[Objectives]To study the introduction performance of pomegranate(Punica granatum)varieties in Shanghai area.[Methods]In this experiment,five pomegranate varieties were introduced,namely‘American 002’pomegranate,‘Huohulu’pomegranate,‘Wanli No.1’pomegranate,‘Yicheng Hongpitian’pomegranate,and‘American Qingpisuan’pomegranate.Then,using these five varieties,various biological traits such as phenology and fruit quality of pomegranate,as well as stress resistance such as heat resistance and cold resistance were studied.[Results]Five varieties of pomegranates began to mature in succession in early September;the smallest single fruit weight was 90 g,and the largest was 110 g;the plants grew fast,the plants were strong,the flowers were single petal,and plants bore fruits which were ornamental and edible.In addition,the pomegranates of these five varieties had good water tolerance and heat resistance,and good cold resistance.[Conclusions]This study is intended to provide a certain reference for the introduction of pomegranate varieties,and also provide a practical basis for the large-scale planting of pomegranate.