| Pyropia haitanensis belonged to Rhodophycophyta,kept mainly in Zhe jiang province,Fujian province,Guangdong province and other coastal areas,is our country unique economic algae in warm temperate zone.P.haitanensis is well known for its nutrition value and hot,its annual output occuoies the nation output of Porphyra 75%.The life history of P.haitanensis is made up of conchocelis and thallus,thallus is the edible part.When spores burst from blister conchocelis,spores can becomethallus,so conchocelis regarded as seed of P.haitanensis.Light is the inter motive of photosynthesis,light quality is important property of light.Light quality affected by depth and clarity in ocean,its has regulation for development,shape,photosynthesis and others of algae.This study regard thallus and free living conchocelis of P.haitanensis as experiment materials,focus on the effect of light quality on grow and physiology of thallus and free living conchocelis of P.haitanensis,analysis the blue light responsive physiological pathways of RNA-Seq.The main results are as follows: 1.Effect of different LED light-qualities on growth and physiological characteristics of free living conchocelis of Pyropia haitanensisThe influence of different light qualities(green 510~550nm,blue 455~475nm,red 580~630nm,white 400~760nm)from Light-Emiting Diode(LED)illuminations on the growth and physiological characteristics of wild free-living conchocelis of Pyropia haitanensis were studied.Results showed that blue light(BL)significantly promoted the growth rate of conchocelis in the cultures.The weight increments of conchocelis under BL were 1.10,1.82,2.17 times higher than those of other conchocelis cultured under white light(WL),green light(GL)and red light(RL),respectively(P<0.05).BL stimulated the synthesis of chlorophyll a and carotenoids.Compared to WL,Gl and RL,the contents of chlorophyll a in BL were increased by 13.77%,47.69%,63.42%,respectively(P<0.05),and the contents of carotenoids in BL were increased by 8.87%,87.07%,97.73%,respectively(P<0.05).BL and WL were conductive to synthesize phycoerythrin rather than GL and RL.However,there were no significant differences ofphycocyanin contents between the conchocelis in the cultures under different LED light qualities(P>0.05).Moreover,BL resulted in the highest activity of carbonic anhydrase,which enhanced 11.36% than those of WL.Compared to WL,both BL and GL significantly stimulated the activity of ribulose bisphosphate carboxylase,which enhanced 28.17% and 61.21%,respectively(P<0.05).In the late growth stage,the conchocelis cultured under RL and GL were discolored and short of satellite chromatophore,even parts of them overflowed their cell inclusions and were hollowed.Wherase,conchocelis under BL and WL were normal,healthy and bright red.The present study provides an experimental foundation for application of LEDs in the asexual propagation of free-living conchocelis in P.haitanensis.Therefore,we can add component of blue-light,decrease red-light and green-light in the asexual propagation of free-living conchocelis in P.haitanensis.2.Transcriptome sequencing and comparative analysis of free-living conchocelis of Pyropia haitanensis under blue light inductionLight had significant effect on the growth and development of P.haitanensis.However,there are limited reports on blue light mediated physiological responses and molecular mechanism.Firstly,the whole transcriptome of free-living conchocelis in P.haitanensis was sequenced in this study,then the transcriptome library established,comparative analysis of gene expression was designed to correlate the effect of blue light and physiological mechanisms on the molecular level.RNA-seq analysis yielded 124527 unigenes with an average length of 585 bp,the GC content of the transcriptome was 59.96%.There are most accounts of annotation unigenes was biological process in GO annotation,24535 unigenes were annotated.Catalytic activity had 8497 unigenes,which was the most among all terms.General function prediction only was 4.09% of all unigens on eggNOG classification,posttranslational modification,protein turnover,chaperones(3.42%)and signal transduction mechanisms(2.90%)comes second.The last three were Nuclear structure(0.11%),Extracellular structures(0.05%)and Cell motility(0.02%).Metabolism and Genetic information processing wrer the most on KEGG annotation,there are 5936 differentially expressed unigenes were detected between blue light and darkness,including 1457 upregulated and 4479 downregulated unigenes.This differentially expressed unigenes were enrichment on Carbon and Nitrogen metabolism,Biosynthesis of amino acids,glyoxylate and dicarboxylate metabolism pathways,suggesting blue light had function in procrss of basic metabolism,protein synthsis,respiration and enzyme activity.3.Effect of different LED light-qualities on growth and physiological character istics of thallus of Pyropia haitanensisThe influence of different light qualities(green 510~550nm,blue 455~475nm,red 580~630nm,white 400~760nm)from Light-Emiting Diode(LED)illuminations on the growth and physiological characteristics of thallus of P.haitanensis were studied.Results showed: that white light significantly promoted the growth rate of conchocelis in the cultures,the highest SGR exceeded blue light(84.54%)and green light(90.28%).After 25 d cultured,the length of thallus topped 51.55 cm under white light,average length under white light was 2.66,3.86 and 2.42 times higher than those of other thallus cultured under blue light,green light and red light respectively(P<0.05).Red light was fast,green light was opposite among three signle light qualities.There were difference on morphology observation and microexamination of thallus of P.haitanensis under different light qualities,thallus under blue light were dark red and cell arranged closer,the color of algae were lighter than white lighter under red and green light.There were significantly difference on the content of pigments,the content of chlorophyll a and carotenoids were highest under blue light,red light were lowest(P<0.05),there were no significant difference between green light and control group(P>0.05).The content of phycobiliprotein,were higher than other groups under blue light,such as phycoerythrin was 1.94 times than control group,phycocyanin was higher of 19% than control group.The content of phycoerythrin was lower than control group under red and green light significantly,phycocyanin was lower of 19.34%(green light)and 11.57%(red light)than control group(P<0.05).After being cultured by 15 d,parthenogenesis happened under blue and green light,cell can develop into conchocelis and grow healthly under blue light,but green light would lead to arrested development or even death. |
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