Drought stress had a predominant effect over heat stress on three tomato cultivars subjected to combined stress

BACKGROUND: Abiotic stresses due to environmental factors could adversely affect the growth and development of crops. Among the abiotic stresses, drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. Considering global climate change, incidence of combined drought and heat stress is likely to increase. The aim of this study was to shed light on plant growth performance and leaf physiology of three tomatoes cultivars (‘Arvento’, ‘LA1994’ and ‘LA2093’) under control, drought, heat and combined stress. RESULTS: Shoot fresh and dry weight, leaf area and relative water content of all cultivars significantly decreased under drought and combined stress as compared to control. The net photosynthesis and starch content were significantly lower under drought and combined stress than control in the three cultivars. Stomata and pore length of the three cultivars significantly decreased under drought and combined stress as compared to control. The tomato ‘Arvento’ was more affected by heat stress than ‘LA1994’ and ‘LA2093’ due to significant decreases in shoot dry weight, chlorophyll a and carotenoid content, starch content and NPQ (non-photochemical quenching) only in ‘Arvento’ under heat treatment. By comparison, the two heat-tolerant tomatoes were more affected by drought stress compared to ‘Arvento’ as shown by small stomatal and pore area, decreased sucrose content, Φ(PSII) (quantum yield of photosystem II), ETR (electron transport rate) and q(L) (fraction of open PSII centers) in ‘LA1994’ and ‘LA2093’. The three cultivars showed similar response when subjected to the combination of drought and heat stress as shown by most physiological parameters, even though only ‘LA1994’ and ‘LA2093’ showed decreased F(v)/F(m) (maximum potential quantum efficiency of photosystem II), Φ(PSII), ETR and q(L) under combined stress. CONCLUSIONS: The cultivars differing in heat sensitivity did not show difference in the combined stress sensitivity, indicating that selection for tomatoes with combined stress tolerance might not be correlated with the single stress tolerance. In this study, drought stress had a predominant effect on tomato over heat stress, which explained why simultaneous application of heat and drought revealed similar physiological responses to the drought stress. These results will uncover the difference and linkage between the physiological response of tomatoes to drought, heat and combined stress and be important for the selection and breeding of tolerant tomato cultivars under single and combine stress

ROS-mediated waterlogging memory, induced by priming, mitigates photosynthesis inhibition in tomato under waterlogging stress

With global climate change, the frequency and intensity of waterlogging events are increasing due to frequent and heavy precipitation. Little is known however about the response of plants to repeated waterlogging stress events. The aim is to clarify physiological regulation mechanisms of tomato plants under repeated waterlogging stress, and whether Trichoderma harzianum can alleviate waterlogging injury. We identified two genotypes of tomato, ‘MIX-002’ and ‘LA4440’, as waterlogging tolerant and sensitive genotypes, respectively, based on plant biomass accumulation. The two tomato genotypes were subjected to a waterlogging priming treatment for 2 days (excess water for 1 cm above substrate surface) followed by a recovery stage for 2 days, and then a second waterlogging stress for 5 days (excess water for 1 cm above substrate surface) followed by a second recovery stage for 3 days. Leaf physiological, plant growth parameters, and the expression of five key genes were investigated. We found that the two genotypes responded differently to waterlogging priming and stress in terms of photosynthesis, reactive oxygen species (ROS), and osmotic regulatory mechanisms. Waterlogging stress significantly increased H2O2 content of ‘MIX-002’, while that of ‘LA4440’ had no significant change. Under waterlogging stress, photosynthesis of the two genotypes treated with waterlogging priming returned to the control level. However, Trichoderma harzianum treatment during the second recovery stage did not show positive mitigative effects. The plants of ‘LA4440’ with priming showed lower peroxidase (POD) activity and proline content but higher H2O2 content than that without priming under waterlogging stress. Under waterlogging stress with priming as compared to without priming, SODCC2 was downregulated in two tomatoes, and AGR2 and X92888 were upregulated in ‘MIX-002’ but downregulated in ‘LA4440’. Overall, the two tomato genotypes exhibited distinct photosynthetic, ROS and osmotic regulatory mechanisms responding to the waterlogging stress. Waterlogging priming can induce stress memory by adjusting stomatal conductance, sustaining ROS homeostasis, regulating osmotic regulatory substances and key gene expressions mediated by H2O2, and thus alleviate the damage on tomato photosynthesis when waterlogging reoccurred

Analysis of search based algorithms for satisfiability of quantified boolean formulas arising from circuit state space diameter problems

Abstract. The sequential circuit state space diameter problem is an important problem in sequential verification. Bounded model checking is complete if the state space diameter of the system is known. By unrolling the transition relation, the sequential circuit state space diameter problem can be formulated as an evaluation for satisfiability of a Quantified Boolean Formula (QBF). This has prompted research in QBFs in the verification community. Most of existing QBF algorithms, such as those based on the DPLL SAT algorithm, are search based. We show that using search based QBF algorithms to calculate the state space diameter of sequential circuits with existing problem formulations is no better than an explicit state space enumeration method. This result holds independent of the representation of the QBF formula. This result is important as it highlights the need to explore non-search based or hybrid of search and non-search based QBF algorithms for the sequential circuit state space diameter problem.

Development of a Gene-Based High Resolution Melting (HRM) Marker for Selecting the Gene <i>ty-5</i> Conferring Resistance to Tomato Yellow Leaf Curl Virus

Tomato yellow leaf curl virus (TYLCV) causes serious yield reductions in China. The use of certain resistance genes in tomato varieties has alleviated the impact of the virus to a certain extent. Recently, varieties with the Ty-1, Ty-2, or Ty-3 genes lost their resistance to TYLCV in some areas in China. New genes should be introduced into tomato to maintain the resistance to TYLCV. Tomato line AVTO1227 has excellent resistance to disease due to the resistance gene ty-5. In this study, we screened different types of markers in a tomato F2 population to compare their accuracy and efficiency. The sequencing analysis results were consistent with the high resolution melting (HRM) marker genotype and field identification results. The result confirmed that the functional marker of ty-5 was accurate and reliable. The single nucleotide polymorphism-based HRM genotyping method established in this study can be used for the selection of breeding parent material, gene correlation analysis, and molecular marker-assisted breeding

Diagnosing single faults for interconnects in SRAM based FPGAs

Abstract: This paper presents a method to diagnose faults in FPGA interconnection resources. A single fault model is given. Under the given model, a diagnosing method is proposed. At most five programming steps in the proposed method is required if adaptive testing scheme is used. For non-adaptive test, eight programming steps is re-quired to diagnose all the possible faults under the given single fault model. The accuracy of the fault diagnosing is one segment for a segment stuck-at or stuck-open fault, a segment pair for a bridge fault, a switch for switch stuck-on or stuck-off fault

Development of a Gene-Based High Resolution Melting (HRM) Marker for Selecting the Gene ty-5 Conferring Resistance to Tomato Yellow Leaf Curl Virus

Tomato yellow leaf curl virus (TYLCV) causes serious yield reductions in China. The use of certain resistance genes in tomato varieties has alleviated the impact of the virus to a certain extent. Recently, varieties with the Ty-1, Ty-2, or Ty-3 genes lost their resistance to TYLCV in some areas in China. New genes should be introduced into tomato to maintain the resistance to TYLCV. Tomato line AVTO1227 has excellent resistance to disease due to the resistance gene ty-5. In this study, we screened different types of markers in a tomato F2 population to compare their accuracy and efficiency. The sequencing analysis results were consistent with the high resolution melting (HRM) marker genotype and field identification results. The result confirmed that the functional marker of ty-5 was accurate and reliable. The single nucleotide polymorphism-based HRM genotyping method established in this study can be used for the selection of breeding parent material, gene correlation analysis, and molecular marker-assisted breeding

Genetic diversity of 23 STR loci of the Guizhou Tujia ethnic minority and the phylogenetic relationships with 22 other populations

Background Short tandem repeats (STR) are highly polymorphic DNA markers utilised in forensic personal identification and human population genetic research. Guizhou Tujia is one of the ancient minority groups in southwest China, however, the population has not been studied using the highly discriminating 23 STR Huaxia Platinum Kit. Aim To obtain genetic data from 23 autosomal STRs in Guizhou Tujia and examine the population’s relationship with others. Subjects and methods A total of 480 individuals from the Guizhou Tujia population were analysed using 23 STR loci of Huaxia Platinum Kit. Allele frequencies and forensic parameters were estimated. Population genetic relationships were calculated by Nei’s genetic distances and visualised using a variety of biostatistical methods. Results A total of 264 alleles were found, with allelic frequencies ranging from 0.0010 to 0.5104. The combined discrimination power (CDP) and the combined probability of paternity (CPE) of 23 STR loci were 0.9999999999999999999999999996 and 0.999999999710422, respectively. Guizhou Tujia showed closer genetic relationships with Hubei Tujia, Guizhou Gelao, and Guizhou Miao than with other populations. Conclusion We first obtained the population genetic data of Guizhou Tujia using the 23 STR system and demonstrated its value in forensic applications. Comprehensive population comparisons showed an evident genetic affinity pattern between populations that are geographically, ethnically and linguistically related

Polyketides with New Delhi Metallo-β-lactamase 1 Inhibitory Activity from <i>Penicillium</i> sp.

Three new polyketide compounds (<b>1–3</b>), a new quinolone alkaloid (<b>4</b>), and seven known polyketide derivatives were identified from the cultures of <i>Penicillium</i> sp. I09F 484, a strain isolated from the rhizosphere soil of the plant <i>Picea asperata</i> from Kanas Lake, Xinjiang, China. Their structures were elucidated by extensive spectroscopic data analysis. The absolute configurations of <b>1</b> and <b>4</b> were established by quantum chemical time-dependent density functional theory electronic circular dichroism calculation and Marfey’s method, respectively. Compounds <b>1</b> and <b>2</b> displayed inhibitory activity against New Delhi metallo-β-lactamase 1 with IC₅₀ values of 94.9 and 87.9 μM, respectively