Gene expression profiling in Pinus sylvestris after methyl jasmonate treatment

Šajā pētījumā noskaidrojām metiljasmonāta ietekmi uz parastās priedes gēnu ekspresijas profilu ar mērķi pārbaudīt tā potenciālu inducētas rezistences veidošanā. Divgadīgus viena klona parastās priedes stādus apstrādājām ar 10 mM metiljasmonāta un pēc divām nedēļām ievācām skuju paraugus. No iegūtajiem paraugiem izdalījām RNS un veicām nāk paaudzes sekvencēšanu ar Ion Torrent PGM platformu, kā arī RT-PCR ekspresijas pārbaudi atsevišķiem gēniem. Sekvencēšanā iegūtos datus analizējām ar RNA-Seq iegūstot paraugos ekspresēto gēnu profilu. Šos rezultātus apkopojām, veidojot gēnu tīklu un iegūstot funkcionalitātes anotācijas. Noskaidrojām, ka apstrāde novirza metabolisma orientāciju no augšanas un attīstības uz aizsardzību. Organisms atrodas inducētā stāvoklī divas nedēļas pēc apstrādes, kas aptiprina metiljasmonāta potenciālu inducētās rezistences veidošanā.In this research the effect of methyl jasmonate on the gene expression profile of Scots pine was determined in order to assess its potential to induce resistance. Two year old Scots pine ramets were treated with 10 mM methyl jasmonate and needle samples were collected two weeks after treatment. RNA was isolated from samples and transcription profiling was performed using the Ion Torrent PGM platform, as well as RT-PCR expression measurment for selected genes. Sequencing data were analyzed with RNA-Seq and gene expression profiles acquired. These results were summarized in a gene network and using gene functionality annotations. Results revealed that treatment with methyl jasmonate diverts metabolic functions from growth and development to defense. The organism is in an induced state two weeks after treatment, which confirms the potential of methyl jasmonate to cause induced resistance

Interactions between seagrasses and mussels: CO₂, pH and calcification

Mussels and other bivalves commonly found in tropical seagrass meadows are thought to increase seagrass productivity, and seagrass photosynthesis, through raising the pH of the surrounding water, has been shown to increase rates of calcification in calcareous algae. The effects of seagrass-driven increases in pH on mussel calcification and possible feedback effects of mussel metabolism on seagrass photosynthesis were studied in a seagrass bed on the south-western coast of Zanzibar, Tanzania. Seagrasses and mussels (Pinna muricata) were enclosed, separately or together, in transparent plastic cylinders. The pH and photosynthesis were measured and seawater samples were taken from the experimental cylinders to determine total alkalinity and total inorganic carbon concentration. Cylinders containing only sediments were exposed to light and dark and used as controls. The results showed no effects of increased pH on calcification rates in the mussels. However, photosynthetic rates of the seagrass Thalassia hemprichii rose by up to 15% in the presence of mussels, possibly as a result of water stirring caused by the mussels’ filter feeding and/or CO2 released by their respiration.</p

Seagrass Meadows in Chwaka Bay : Socio-ecological and Management Aspects

The shallow-water seascape of Chwaka Bay consists of diverse habitats including coral reefs, sand/mud flats, algal belts and mangrove forests, but the embayment is primarily characterized by its widespread and highly productive seagrass beds. The Bay is a unique seagrass diversity “hotspot”, with eleven species observed, from small, fast-growing and thin-leaved “pioneer” species like Halophila ovalis and H. stipulacea to large, slower-growing “climax species” with thick and long leaves like Thalassodendron ciliatum and Enhalus acoroides. Consequently, it is not surprising that the small-scale subsistence fishery of Chwaka Bay can be seen as a seagrass fishery, with catches consisting primarily of species intimately associated with the seagrass meadows (de la Torre-Castro and Rönnbäck 2004; de la Torre-Castro 2006).Seagrasses are a polyphyletic group of marine vascular, rhizomal plants (den Hartog 1970, 12-13), which form stands of varying sizes usually called “beds” or “meadows” in intertidal and subtidal coastal waters across the globe. Seagrass meadows typically occur on nearshore soft bottoms (although some species are found on rocky bottoms) in single- or mixed-species assemblages, with the typical wide range from tropical to boreal margins of coastal waters (Green and Short 2003, 21-22). They form one of the most productive aquatic ecosystems on Earth (Duarte and Chiscano 1999) and in most areas occur intermixed with other large primary producers like macroalgae. Seagrass ecosystems support multiple ecological functions, including nursery grounds, food and refuge for many benthic

Photorespiration and Carbon Limitation Determine Productivity in Temperate Seagrasses

The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC) and O(2) in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O(2) levels and lower DIC levels. Gross photosynthetic O(2) evolution was then measured in this pretreated seawater (pH, 7.8–9.8; high to low DIC:O(2) ratio) at both natural and low O(2) concentrations (adjusted by N(2) bubbling). The presence of photorespiration was indicated by a lower gross O(2) evolution rate under natural O(2) conditions than when O(2) was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime) and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH). The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow waters