The soybean sugar transporter GmSWEET6 participates in sucrose transport towards fungi during arbuscular mycorrhizal symbiosis.

In arbuscular mycorrhizal (AM) symbiosis, sugars in root cortical cells could be exported as glucose or sucrose into peri-arbuscular space for use by AM fungi. However, no sugar transporter has been identified to be involved in sucrose export. An AM-inducible SWEET transporter, GmSWEET6, was functionally characterised in soybean, and its role in AM symbiosis was investigated via transgenic plants. The expression of GmSWEET6 was enhanced by inoculation with the cooperative fungal strain in both leaves and roots. Heterologous expression in a yeast mutant showed that GmSWEET6 mainly transported sucrose. Transgenic plants overexpressing GmSWEET6 increased sucrose concentration in root exudates. Overexpression or knockdown of GmSWEET6 decreased plant dry weight, P content, and sugar concentrations in non-mycorrhizal plants, which were partly recovered in mycorrhizal plants. Intriguingly, overexpression of GmSWEET6 increased root P content and decreased the percentage of degraded arbuscules, while knockdown of GmSWEET6 increased root sugar concentrations in RNAi2 plants and the percentage of degraded arbuscules in RNAi1 plants compared with wild-type plants when inoculated with AM fungi. These results in combination with subcellular localisation of GmSWEET6 to peri-arbuscular membranes strongly suggest that GmSWEET6 is required for AM symbiosis by mediating sucrose efflux towards fungi.

Regulation of proline metabolism, AsA-GSH cycle, cadmium uptake and subcellular distribution in Brassica napus L. under the effect of nano-silicon.

Cadmium (Cd) is known to have detrimental effects on plant growth and human health. Recent studies showed that silicon nanoparticles (SNPs) can decrease Cd toxicity in plants. Therefore, a study was conducted using 50 µM Cd and 1.50 mM SNPs to investigate Cd uptake, subcellular distribution, proline (Pro) metabolism, and the antioxidant defense system in rapeseed seedlings. In this study, results indicated that Cd stress negatively affected rapeseed growth, and high Cd contents accumulated in both shoots and roots. However, SNPs significantly decreased Cd contents in shoots and roots. Moreover, substantial increases were found in root fresh weight by 40.6% and dry weight by 46.6%, as well as shoot fresh weight by 60.1% and dry weight by 113.7% with the addition of SNPs. Furthermore, the addition of SNPs alleviated oxidative injury by maintaining the ascorbate-glutathione (AsA-GSH) cycle and increased Pro biosynthesis which could be due to high activities of Δ1-pyrroline-5-carboxylate synthase (P5CS) and reductase (P5CR) and decreased proline dehydrogenase (ProDH) activity. Furthermore, the addition of SNPs accumulated Cd in the soluble fraction (42%) and cell wall (45%). Results indicate that SNPs effectively reduce Cd toxicity in rapeseed seedlings which may be effective in promoting both rapeseed productivity and human health preservation.

Potential application of melatonin in reducing boron toxicity in rice seedlings through improved growth, cell wall composition, proline, and defense mechanisms.

Melatonin (MT) has been demonstrated to provide defense against both biotic and abiotic stressors. Boron toxicity (BT) can significantly limit the growth and production of plants. However, few studies have been conducted on whether MT is effective in attenuating B toxicity in different plants. In order to evaluate the efficacy of exogenous MT treatment in reducing the negative impact of BT on rice seedlings, this study examined the influence of MT on growth, antioxidant capacity, cell wall composition, and proline metabolism in rice seedlings under hydroponics. Four treatments were established: MT (50 µM), MT + BT (50 µM MT + 800 µM B), BT (800 µM), and CK (control) in a completely randomized design. The results indicate that BT had a significant detrimental effect on the shoot length, root length, and root and shoot fresh weights of rice seedlings by 11.96%, 27.77%, 25.69%, and 18.67%, respectively as compared to the control treatment. However, exogenous MT application increased these parameters and reduced B accumulation in aboveground parts (14.05%) of the plant. Exogenous MT also increased the endogenous melatonin content and antioxidant enzyme activities (64.45%, 71.61%, 237.64%, and 55.42% increase in superoxide dismutase, ascorbate peroxidase, and peroxidase activities, respectively), while decreasing reactive oxygen species levels and oxidized forms of glutathione and ascorbic acid. Additionally, MT enhanced the biosynthesis of proline by decreasing proline dehydrogenase (ProDH) and increasing the GSH (glutathione) and ASA (ascorbic acid) contents. Exogenous MT also increased cell wall components that can increase B adsorption to the cell wall. Overall, these findings suggest that MT application can be a potential solution for strengthening the stress tolerance of rice seedlings, particularly under conditions of B toxicity. In regions where soil contains high levels of boron, the use of MT could enhance rice crop yields and quality.

Effect of nano-silicon on the regulation of ascorbate-glutathione contents, antioxidant defense system and growth of copper stressed wheat (Triticum aestivum L.) seedlings.

Copper (Cu2+) toxicity can inhibit plant growth and development. It has been shown that silicon (Si) can relieve Cu2+ stress. However, it is unclear how Si-nanoparticles (SiNPs) relieve Cu2+ stress in wheat seedlings. Therefore, the current study was conducted by setting up four treatments: CK, SiNP: (2.5 mM), Cu2+: (500 µM), and SiNP+Cu2+: (2.5 mM SiNP+500 µM Cu2+) to explore whether SiNPs can alleviate Cu2+ toxicity in wheat seedlings. The results showed that Cu2+ stress hampered root and shoot growth and accumulated high Cu2+ concentrations in roots (45.35 mg/kg) and shoots (25.70 mg/kg) of wheat as compared to control treatment. Moreover, Cu2+ treatment inhibited photosynthetic traits and chlorophyll contents as well as disturbed the antioxidant defense system by accumulating malondialdehyde (MDA) and hydrogen peroxidase (H2O2) contents. However, SiNPs treatment increased root length and shoot height by 15.1% and 22%, respectively, under Cu2+ toxicity. Moreover, SiNPs application decreased MDA and H2O2 contents by 31.25% and 19.25%, respectively. SiNPs increased non-enzymatic compounds such as ascorbic acid-glutathione (AsA-GSH) and enhanced superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbic peroxidase (APX) activities by 77.5%, 141.7%, 68%, and 80%, respectively. Furthermore, SiNPs decreased Cu2+ concentrations in shoots by 26.2%, as compared to Cu2+ treatment alone. The results concluded that SiNPs could alleviate Cu2+ stress in wheat seedlings. The present investigation may help to increase wheat production in Cu2+ contaminated soils.

Transcriptomic analysis reveals the possible roles of sugar metabolism and export for positive mycorrhizal growth responses in soybean.

To elucidate molecular mechanisms controlling differential growth responses to root colonization by arbuscular mycorrhizal (AM) fungi varying in colonization and cooperative behavior, a pot experiment was carried out using two soybean genotypes and three AM inocula. The results showed that inoculation by cooperative Rhizophagus irregularis (Ri) or less cooperative Glomus aggregatum with high AM colonization (Ga-H) significantly promoted plant growth compared with inoculation by G. aggregatum with low AM colonization (Ga-L). A comparative RNA sequencing analysis of the root transcriptomes showed that fatty acid synthesis pathway was significantly enriched in all three AM inoculation roots. However, sugar metabolism and transport were significantly enriched only in Ri and Ga-H inoculation, which was consistent with positive growth responses in these two inoculation treatments. Accordingly, the expression levels of the key genes related to sugar metabolism and transport were also upregulated in Ri and Ga-H roots compared with Ga-L roots. Of them, two sugars will eventually be exported transporters (SWEET) transporter genes, GmSWEET6 (Glyma.04G198600) and GmSWEET15 (Glyma.06G166800), and one invertase (Glyma.17G227900) gene were exclusively induced only in Ri and Ga-H roots. Promoter analyses in transgenic soybean roots further demonstrated that GUS driven by the GmSWEET6 promoter was highly expressed in arbuscule-containing cortical cells. Additionally, Ri and Ga-H inoculation increased the contents of sucrose, glucose and fructose in both shoots and roots compared with those of Ga-L and non-mycorrhizal. These results imply that positive mycorrhizal growth responses in plants might mostly be due to the stimulation of photosynthate metabolism and transport by AM fungal inoculum with high colonization capabilities.

[Improvement of Digital Capsule Endoscopy System and Image Interpolation].

Traditional capsule image collects and transmits analog image, with weak anti-interference ability, low frame rate, low resolution. This paper presents a new digital image capsule, which collects and transmits digital image, with frame rate up to 30 frames/sec and pixels resolution of 400 x 400. The image is compressed in the capsule, and is transmitted to the outside of the capsule for decompression and interpolation. A new type of interpolation algorithm is proposed, which is based on the relationship between the image planes, to obtain higher quality colour images. capsule endoscopy, digital image, SCCB protocol, image interpolation

Arbuscular mycorrhizal growth responses are fungal specific but do not differ between soybean genotypes with different phosphate efficiency.

BACKGROUND AND AIMS: Arbuscular mycorrhizal (AM) fungi play a key role in the phosphate (P) uptake of many important crop species, but the mechanisms that control their efficiency and their contribution to the P nutrition of the host plant are only poorly understood. METHODS: The P uptake and growth potential of two soybean genotypes that differ in their root architectural traits and P acquisition efficiency were studied after colonization with different AM fungi and the transcript levels of plant P transporters involved in the plant or mycorrhizal P uptake pathway were examined. KEY RESULTS: The mycorrhizal growth responses of both soybean genotypes ranged from highly beneficial to detrimental, and were dependent on the P supply conditions, and the fungal species involved. Only the colonization with Rhizophagus irregularis increased the growth and P uptake of both soybean genotypes. The expression of GmPT4 was downregulated, while the mycorrhiza-inducible P transporter GmPT10 was upregulated by colonization with R. irregularis Colonization with both fungi also led to higher transcript levels of the mycorrhiza-inducible P transporter GmPT9, but only in plants colonized with R. irregularis were the higher transcript levels correlated to a better P supply. CONCLUSIONS: The results suggest that AM fungi can also significantly contribute to the P uptake and growth potential of genotypes with a higher P acquisition efficiency, but that mycorrhizal P benefits depend strongly on the P supply conditions and the fungal species involved.

A complexity-efficient and one-pass image compression algorithm for wireless capsule endoscopy.

BACKGROUND: As an important part of the application-specific integrated circuit (ASIC) in wireless capsule endoscopy (WCE), the efficient compressor is crucial for image transmission and power consumption. OBJECTIVE: In this paper, a complexity-efficient and one-pass image compression method is proposed for WCE with Bayer format images. The algorithm is modified from the standard lossless algorithm (JPEG-LS). METHODS: Firstly, a causal interpolation is used to acquire the context template of a current pixel to be encoded, thus determining different encoding modes. Secondly, a gradient predictor, instead of the median predictor, is designed to improve the accuracy of the predictions. Thirdly, the gradient context is quantized to obtain the context index (Q). Eventually, the encoding process is achieved in different modes. RESULTS: The experimental and comparative results show that our proposed near-lossless compression method provides a high compression rate (2.315) and a high image quality (46.31 dB) compared with other methods. CONCLUSION: It performs well in the designed wireless capsule system and could be applied in other image fields.

[A method for bleeding detection in endoscopy images using SVM].

Because the huge number of images of the digestive tract by Wireless Capsule Endoscopy (WCE) are left to the medical personnels detected by their eyes, huge burden leaves to doctors. This article provides a classification of method based on SVM (Support Vector Machine) for the capsule endoscopy bleeding intelligent recognition. We created a new kind of feature parameter, and the experiment result can reach 83% specificity and 94% sensitivity.