Comparative transcriptomics reveals new insights into melatonin-enhanced drought tolerance in naked oat seedlings.

The growth and development of naked oat (Avena nuda L.) seedlings, a grain recognized as nutritious and healthy, is limited by drought. Melatonin plays a positive role in plants under drought stress. However, its function is unclear in naked oats. This study demonstrated that melatonin enhances drought stress tolerance in oat seedlings. Melatonin application alleviated the declining growth parameters of two naked oat varieties, Huazao No.2 (H2) and Jizhangyou No.15 (J15), under drought stress by increasing the chlorophyll content and photosynthetic rate of leaves. Melatonin pretreatment induced differential gene expression in H2 and J15 under drought stress. Subsequently, the differential gene expression responses to melatonin in the two varieties were further analyzed. The key drought response transcription factors and the regulatory effect of melatonin on drought-related transcription factors were assessed, focusing on genes encoding proteins in the ABA signal transduction pathway, including PYL, PP2C, ABF, SNRK2, and IAA. Taken together, this study provides new insights into the effect and underlying mechanism of melatonin in alleviating drought stress in naked oat seedlings.

Effects of drought stress during critical periods on the photosynthetic characteristics and production performance of Naked oat (Avena nuda L.).

Revealing the effects of drought stress on the photosynthetic characteristics and yield of naked oats (Avena nuda L.) is significant for enhancing the productivity of oats. In this study, a potted experiment consisting of four water levels was conducted in the Bashang area of Hebei Province, China. The drought stress period was established as the continual 8 days during the jointing-heading stage. The aims were to reveal the impacts of drought stress on the photosynthetic characteristics and yield of naked oats during the critical stage. The results showed that the photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) decreased under all conditions of drought stress. The intercellular CO2 concentration (Ci) decreased under light drought stress, while it increased under moderate and severe drought stress. The initial chlorophyll fluorescence rate (Fo) increased by 9.03-50.92% under drought stress, and the maximum fluorescence rate (Fm) decreased by 8.49-19.73% under drought stress. The photochemical efficiency (Fv/Fm) increased by 10.37-24.12% under drought stress. The yields decreased by 9.5-12.7%, 16.8-27.0% and 44.1-47.7% under light, moderate and severe drought stress during the critical stage, respectively. The grains per panicle decreased by 1.7-12.5%, 8.3-24.3% and 32.7-34.2% under light, moderate and severe drought stress conditions, respectively. The 1000-grain weight decreased by 5.7-8.6%, 12.7-14.5% and 16.8-19.1% under light, moderate and severe drought stress conditions, respectively. The panicle numbers did not vary significantly among the different drought stress treatments. The photosynthetic rate, stomatal conductance and transpiration all had significant positive relationships with the yield of naked oat (P < 0.01). Parameters of PS II except for Fo all had significant positive relationships with the yield of naked oats (P < 0.05). This study is significant for enhancing the production efficiency of naked oat under drought stress.

[Contrast-enhanced ultrasound imaging features of diabetic foot ulcers].

OBJECTIVE: To investigate contrast-enhanced ultrasound imaging features of diabetic foot ulcers. METHODS: Sixteen patients with diabetic foot ulcers underwent conventional and contrast-enhanced ultrasound examinations, and the features of contrast-enhanced ultrasound imaging were analyzed. Pathological examination was also carried out in some cases. RESULTS: Contrast-enhanced ultrasound showed slow enhancement in the artery phase in the 16 ulcers after administration of SonoVue. The mean time of initial enhancement was 30.02 ± 2.35 s, and the mean time for the occurrence of peak enhancement was 37.54 ± 4.13 s. In 5 cases a homogeneous enhancement pattern was clearly displayed, and in the other 11 cases, a pattern of homogenous peripheral enhancement with non-enhanced patches within the ulcers was found. Contrast-enhanced ultrasound showed a greater ulcerous area than conventional ultrasound. CONCLUSION: Contrast-enhanced ultrasound is a valuable means for evaluating the ulcerous area and the treatment efficacy for diabetic foot ulcers.

Activation tagging, an efficient tool for functional analysis of the rice genome.

Over the past 6 years, we have generated about 50,000 individual transgenic rice plants by an Agrobacterium-mediated transformation approach with the pER38 activation tagging vector. The vector contains tandemly arranged double 35S enhancers next to the right border of T-DNA. Expression analysis by reverse transcription-PCR indicates that the activation efficiency is high if the genes are located within 7 kb of the inserted double 35S enhancers. Comparative field phenotyping of part of the activation tagging and enhancer trapping populations in two generations (6,000 and 6,400 lines, respectively, in the T(0) generation, and 36,000 and 32,000 lines, respectively, in the T(1) generation) identified about four hundred dominant mutants. Characterization of a dominant mutant with a large leaf angle (M107) suggests that this mutant phenotype is caused by enhanced expression of CYP724B1/D11. The activation tagging pool described in this paper is a valuable alternative tool for functional analysis of the rice genome.