Search

Alternaria alternata is a pathogenic fungus that infects jujube fruit and leads to serious economic losses. In this paper, the antifungal activity of chitosan combined with sodium silicate against A. alternata in vitro and in vivo was investigated, and the possible antimicrobial mechanisms were explored. Results showed that the spore germination and colony expansion of A. alternata were significantly inhibited by chitosan. Chitosan treatment induced the leakages of intercellular electrolytes, nucleic acids, and soluble protein of A. alternata. Meanwhile, chitosan damaged the cell morphology and membrane integrity of A. alternata. The combination of chitosan and sodium silicate was more effective than chitosan alone. In addition, the effect of chitosan and sodium silicate could significantly decrease natural rot rate and delay lesion expansion of winter jujube. Collectively, chitosan combined with sodium silicate had the potential to control postharvest diseases of fruit caused by A. alternata. [ABSTRACT FROM AUTHOR]

The potassium (K+) transporter/high-affinity K+/K+uptake transporters (KT/HAK/KUP), which contribute to K+ uptake, transport and allocation, take an indispensible part in ion homeostasis, as well as in plant adaptation to disadvantageous environmental stresses. However, molecular mechanisms in terms of K+ nutrition in fruit crops are still largely unknown. In this work, we isolated 15 KT/HAK/KUP transporter genes in strawberry (designated as FveKUP1 to FveKUP15), and checked their expression under both normal and K+ deficient conditions. Quantitative real-time PCR analyses indicated that most FveKUPs were largely expressed in flowers, with a responsive expression to K+ deficiency. Among these FveKUPs, FveKUP8 was the most abundantly expressed gene in all tested tissues, and its expression was significantly reduced by K+ deficiency. Further functional complementation experiment in bacterial mutant indicated that FveKUP8 can utilize external K+ under neutral proton environment, and might be a dominant K+ transporter during the flowering of strawberry plants. Our findings suggest that FveKUP8 is involved in K+ homeostasis in strawberry, and could be used as a potential gene for the molecular breeding of high K+ efficiency plants. [ABSTRACT FROM AUTHOR]

Sugar beet is an important economic crop because of its high sucrose concentration in the roots. However, information on the relationship between sucrose metabolism-related enzymes and root yield is scarce. In this study, we aimed to investigate the activity of sucrose phosphate synthase (SPS), sucrose synthase (SS), and invertase (INV), which are key enzymes in sucrose metabolism, in relation to root weight and sucrose content in different parts of the sugar beet plant over the growth cycle. Results showed that root SPS, SS, and INV activities positively correlated with sucrose content. SPS activity increased with maturity, reaching the highest rates at harvest, whereas INV activity was high at the early stages and gradually decreased with maturity. No association was found between SPS, SS, or INV activity in the leaves and petioles with sucrose content, or between root weight and sucrose content. Overall, our results provide new insights into the underlying mechanism of sucrose metabolism and will allow faster development of sugar beet cultivars with high sucrose content. [ABSTRACT FROM AUTHOR]

The relationship between active oxygen metabolism and resistance to late blight (Phytophthora infestans) in potato (Solanum tuberosum L.) was studied for 72 h post-inoculation by comparing three resistant cultivars (low disease index) with three susceptible ones (high disease index). Activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and the content of ascorbic acid (ASA), were higher in the resistant cultivars than in the susceptible ones. The production rate of the superoxide anion radical (O2−) was lower in the resistant cultivars than in the susceptible ones. These changes, which were associated with the potato plant’s response to infection with P. infestans, provide some insight into the physiological basis of resistance and may also provide a screening tool for resistance to late blight. [ABSTRACT FROM AUTHOR]

Many plants accumulate betaine in response to water stress. The betaine aldehyde dehydrogenase (BADH) is the key enzyme in betaine biosynthesis in plants and can be regulated by BADH gene. A pot experiment was conducted to compare the relation of betaine content and BADH gene expression in two sugarbeet ( Beta vulgaris L.) varieties differing in drought tolerance. We observed an evident correlation between the transcript up-regulation and the betaine accumulation under water stress. Results showed that the betaine content and BADH gene expression in the drought tolerant variety, was significantly increased under drought stress. The betaine accumulation and BADH gene expression might function as one response to eliminate the negative effects of drought and may play a critical role in maintaining photosynthetic activity in sugarbeet plants under water stress. [ABSTRACT FROM AUTHOR]

The China Spallation Neutron Source (CSNS) is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz. In this paper, we focus on the physical design of CSNS target station and neutron instruments. Under optimized design, the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators. Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications. Layout of neutron instruments are conceptually planned for total 20 beamlines, the configuration and specification have been determined for three day-one neutron instruments. All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW. [ABSTRACT FROM AUTHOR]