Evolutionary expansion and functional divergence of sugar transporters in Saccharum (S. spontaneum and S. officinarum)

The sugar transporter (ST) family is considered to be the most important gene family for sugar accumulation, but limited information about the ST family in the important sugar-yielding crop Saccharum is available due to its complex genetic background. Here, 105 ST genes were identified and clustered into eight subfamilies in Saccharum spontaneum. Comparative genomics revealed that tandem duplication events contributed to ST gene expansions of two subfamilies, PLT and STP, in S. spontaneum, indicating an early evolutionary step towards high sugar content in Saccharum. The analyses of expression patterns were based on four large datasets with a total of 226 RNA sequencing samples from S. spontaneum and Saccharum officinarum. The results clearly demonstrated 50 ST genes had different spatiotemporal expression patterns in leaf tissues, 10 STs were specifically expressed in the stem, and 10 STs responded to the diurnal rhythm. Heterologous expression experiments in the defective yeast strain EBY.VW4000 indicated STP13, pGlcT2, VGT3, and TMT4 are the STs with most affinity for glucose/fructose and SUT1_T1 has the highest affinity to sucrose. Furthermore, metabolomics analysis suggested STP7 is a sugar starvation-induced gene and STP13 has a function in retrieving sugar in senescent tissues. PLT11, PLT11_T1, TMT3, and TMT4 contributed to breaking the limitations of the storage sink. SUT1, SUT1_T1, PLT11, TMT4, pGlcT2, and VGT3 responded for different functions in these two Saccharum species. This study demonstrated the evolutionary expansion and functional divergence of the ST gene family and will enable the further investigation of the molecular mechanism of sugar metabolism in Saccharum.     

Mechanism of resistance to the spotted stalk borer,Chilo sacchariphagus,in the sugarcane cultivar R570

Resistance in sugarcane [Saccharum spec. (Poaceae)] to the spotted stalk borer, Chilo sacchariphagus (Bojer) (Lepidoptera: Pyralidae), was studied by comparing feeding behaviour on resistant cv. R570 and susceptible cv. R579. In a field survey, the feeding behaviour of C. sacchariphagus larvae was described to identify their feeding sites on the plant. In a greenhouse artificial infestation study, we compared the establishment of larvae on potted plants. In laboratory choice and no‐choice experiments, we studied the establishment of larvae on plant organs (stalk, sheath, leaf spindle). Study of the feeding behaviour showed that: (1) first to fourth instars are able to feed on stalk, sheath, and leaf spindle, (2) boring into the stalk occurs mostly in the four uppermost internodes, and (3) most young larvae bore through the abaxial surface of leaf sheaths to reach the stalk. In greenhouse experiments, we observed an early two‐fold reduction of the number of larvae on R570 plants within the first 48 h after infestation. In laboratory experiments, larval antixenosis was demonstrated at the abaxial surface of R570 leaf sheath, but was observed neither in the leaf spindle nor in the stalk. First, second, and third instars were susceptible to this antixenosis. We hypothesize that the main resistance mechanism in R570 is an early reduction of larval establishment on plants, due to antixenosis located at the abaxial surface of leaf sheaths.     

冰冻切片法在植物微管骨架研究中的应用

介绍了冰冻切片法研究植物微管骨架的一般程序和技术上的一些改进,结果证明,改进的冰冻切片技术,可以对植物不同类型的细胞进行很好的标记。实验结果表明,甘蔗正在迅速伸长的幼叶分布的微管类型主要是与细胞伸长轴方向垂直的周质微管,幼叶基部尤其是第三幼叶基部分布的主要是与细胞伸长轴方向平行的周质微管。表明冰冻切片法在植物微管骨架的研究中具有广阔的应用前景。     

多胞锈菌属（锈菌目，多胞锈菌科）3新种和两中国新记录

报道了多胞锈菌属Phragmidium(多胞锈菌科Phragmidiaceae)的3个新种和两中国新记录。新种是采自香莓Rubus pungens var. oldhamii上的多隔多胞锈菌P.multiseptatum、采自峨眉蔷薇Rosa omeiensis上的粗壮多胞锈菌P. robustum以及采自华中悬钩子Rubus cockburnianus上的西藏多胞锈菌P. tibeticum。中国新记录是二花悬钩子Rubus biflorus和掌叶悬钩子R. pentagonus上的八室多胞锈菌P. octoloculare以及秀丽悬钩子Rubus amabilis、香莓R.pungens var.oldhamii、柔毛针刺悬钩子R.pungens var. villosus和西藏悬钩子R. thibetanus上的香莓多胞锈菌P. rubi-oldhami。     

Comparative investigations on the distribution of sucrose synthase activity and invertase activity within growing, mature and old leaves of some C3 and C4 plant species

Sucrose synthase (EC 2.4.1.13) activity in young growing leaves was highest in the leaf base in eggplants ( Solanum melongena L.), cassava ( Manihot esculenta Crantz), grapevine ( Vitis vinifera L.), and in the leaf sheath of sugar cane ( Saccharum of ficinarum L.) and maize ( Zea mays L.). In addition, increasing sucrose synthase activity was measured towards the edge of growing eggplant leaves while the activity in mature leaves was highest in the midrib. The activity of acid and alkaline invertase was very low in the midrib but higher in the blade of fully expanded eggplant leaves. Highest invertase activities were found in younger growing leaves. It was concluded that in growing leaves a close relationship might exist between the activity of sucrose synthase and the import of sucrose from source leaves.
Detachment of mature eggplant leaves led to a 2- to 3-fold increase of sucrose synthase activity in blade and midrib of these leaves. In contrast, invertase activity decreased after detachment in both leaf blade and midrib. It was concluded that the rise in sucrose synthase activity might have been caused by the observed increase of sucrose concentration in detached leaves and that sucrose synthase might have an important role in the regulation of sucrose content of the conducting tissue.     

Detection of Colletotrichum falcatum causing red rot of sugarcane by enzyme-linked immunosorbent assay

Red rot disease of sugarcane caused by Colletotrichum falcatum Went is one of the most destructive diseases of sugarcane (Saccharum officinarum L.) worldwide. The pathogen spreads primarily through infected sugarcane setts and hence the use of disease-free setts is essential to prevent the disease. In order to develop immunological method for detection of C. falcatum, two proteins with molecular weights of 27 kDa and 45 kDa were purified from the mycelium of C. falcatum race Cf 05 and used as antigen source to raise polyclonal antibodies in NewZealand white rabbit. The developed polyclonal antibodies were tested for detection of C. falcatum by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. The polyclonal antibodies specifically detected C. falcatum in extracts from infected plants, both in immunoblot and ELISA. The ELISA results showed that the developed polyclonal antibodies were highly specific to C.falcatum. The developed antibodies were very sensitive and could detect C.falcatum proteins even at a dilution of 1:50,000. Higher ELISA absorbance values were recorded even at an antigen dilution of 1:500. In western blot analysis, protein bands with molecular weights of 27 kDa and 45 kDa reacting to antisera raised against 27 kDa and 45 kDa mycelial proteins of C. falcatum, respectively, were detected in protein samples from red rot infected canes. The high specific reactivity and sensitivity of the antisera indicate its potential suitability for ELISA-based detection of C. falcatum.     

Isolation of specific receptors from Xanthomonas albilineans cell walls for lectins-like glycoproteins of sugarcane

Abstract

Two families of sugarcane glycoproteins differing in their molecular mass have been isolated from sugarcane stalks. These glycoproteins specifically bind to cell wall receptors of Xanthomonas albilineans, a sugarcane pathogen, producing bacterial agglutination. Bound glycoproteins can be desorbed from bacterial cell walls by galactitol, a component of the glycosidic moiety of the sugarcane protein. This indicates that sugarcane glycoproteins bind through their glycosidic rest to the peptide moiety of the bacterial receptor. Several cell wall receptors have been isolated by affinity chromatography and separated by capillary electrophoresis.     

Immunotherapeutic effects of some sugar cane (Saccharum officinarum L.) extracts against coccidiosis in industrial broiler chickens

Present paper reports the effects of aqueous and ethanolic extracts of sugar cane (Saccharum officinarum L.) juice and bagasse, respectively on protective immune responses in industrial broiler chickens against coccidiosis. Immunotherapeutic efficacies of the extracts were measured by evaluating their effect on body weight gain, oocyst shedding, lesion score, anti-coccidial indices, per cent protection and elicited serum antibody responses against coccidiosis. Results revealed a significantly lower (P < 0.05) oocyst shedding and mortality in chickens administered with sugar cane extracts as compared to control. Further, significantly higher (P < 0.05) body weight gains and antibody responses were detected in chickens administered with sugar cane extracts as compared to chickens of control group. Moreover, ethanolic extract showed higher anti-coccidia index (227.61) as compared to aqueous extract (192.32). The organ body weight ratio of the lymphoid organs of experimental and control groups were statistically non-significant (P > 0.01). These results demonstrated that both ethanolic and aqueous extracts of sugar cane possess immune enhancing properties and their administration in chickens augments the protective immunity against coccidiosis.     

Saccharification of Kans grass using enzyme mixture from Trichoderma reesei for bioethanol production

Bioethanol is one of the alternatives of the conventional fossil fuel. In present study, effect of different carbon sources on the production of cellulolytic enzyme (CMCase) from Trichoderma reesei at different temperatures, duration and pH were investigated and conditions were optimized. Acid treated Kans grass (Saccharum sponteneum) was subjected to enzymatic hydrolysis to produce fermentable sugars which was then fermented to bioethanol using Saccharomyces cerevisiae. The maximum CMCase production was found to be 1.46 U mL⁻¹ at optimum condition (28 °C, pH 5 and cellulose as carbon source). The cellulases and xylanase activity were found to be 1.12 FPU g⁻¹ and 6.63 U mL⁻¹, respectively. Maximum total sugar was found to be 69.08 mg/g dry biomass with 20 FPU g⁻¹ dry biomass of enzyme dosage under optimum condition. Similar results were obtained when it was treated with pure enzyme. Upon fermentation of enzymatic hydrolysate, the yield of ethanol was calculated to be 0.46 g g⁻¹.