| The armored scale is a common taxonomic group of pests in the mangrove,which is now serious pest in the mangrove in Fujian and Guangxi province.However,there is few research on the outbreak and damage characteristics of the scales.In this study,through field investigation,molecular marker technology,plant physiology and transcriptomics analysis methods,we want to investigate the species,population dynamics and damage characteristics of the armored scale on Kandelia obovata mainly in Xiamen mangrove forest.The results are as follows:1.Thirteen kinds of armored scales are found in the mangrove and eight kinds of them are found in Xiamen mangrove forest,including Pseudaulacaspis cockerelli,Mytilaspis sp.,Parlatoria sp.,Aonidiella sp.,Chrysomphalus sp.,Octaspidiotus sp.,Chionaspis pinifoliae and Diaspidinae sp..Besides,Parlatoria pergandii,Aonidiella pini,Chrysomphalus bifasciculatus,Aonidiella citrina and another armored scale belonging to Diaspidinae are also found in in the mangrove in Zhangzhou,Quanzhou,Ningde,etc.Parlatoria spp.,Aonidiella spp.,Octaspidiotus spp.,Chionaspis pinifoliae,Chrysomphalus bifasciculatus,and Diaspidinae spp.are reported for the first time in the mangrove forest.2.NJ trees are constructed with 28S and COI sequences of 13 kinds of armored scales on 12 kinds of plants,including Kandelia obovata.The congeneric species or relatives of armored scales can grouped into one branch.So we think the 28S sequence and COI sequence can be used to identification of the armored scales in the mangrove forest.It is also found that the haplotypes,nucleotide diversity and genetic diversity of P.cockerelli is very low through COI sequences analysis.3.P.cockerelli and Mytilaspis sp.are main pests in Xiamen mangrove.P.cockerelli mainly harms K.obovata in Songyu Wharf and Taidi,the harm of which peaks in May and December.The infection rate and quantity of Mytilaspis sp.are lower than that of P.cockerelli,peaking at Songyu Wharf in July and December,and peaking at Jimei district in May;Chionaspis pinifoliae only appears in Yundang Lake on the K.obovata,the population of which is the highest in March;The number and infection rate of other armored scales are low,and they are little harmful.In the different seasons,the number of first instar nymphs,second instar nymphs and female adults on K.obovata leaves in spring are the highest and the number of them are the lowest in autumn at Songyu Wharf.4.In different ages of leaves,the younger nymphs of P.cockerelli are mainly distributed on the tender leaves of K.obovata branches,while the older nymphs and adults are mainly on the mature and old leaves.At different locations,the number of P.cockerelli and leaf infection rate are highest on the inner side of the mangrove at Songyu Wharf and the outer side is lower.In different constituents of mangrove forest,the number of Mytilaspis sp.in the mixed area of K.obovata and Sonneratia apetala is significantly lower than that in the pure K.obovatq area,while the number of P.cockerelli is not significantly different.In different height,the K.obovata and its leaves of 1.0-2.0 m are the most severely damaged by P.cockerelli.5.The result of correlation analysis shows that there is a significant correlation between humidity and the population of two kinds of armored scales,P.cockerelli and Mytilaspis sp.,an extremely significant correlation between humidity and the population of Chionaspis pinifoliae.6.With increasing damage of armored scales,the photosynthetic rate,leaf chlorophyll,chloroplast total pigment content,stomatal conductance and transpiration rate of K.obovata leaves decrease significantly.The contents of soluble protein,MDA,SOD,and PPO in the damaged leaves increased significantly,while the contents of soluble sugar,free proline,and CAT increase firstly and then decrease.7.Through transcriptome sequencing and assembly,96197 unigenes are obtained from the damaged leaves of K.obovata,85966 unigenes of which are annotated.The most significant differentially expressed genes are detected between undamaged leaves and severely damaged leaves(NL-HL),and the up-regulated expression genes increased significantly.The differentially expressed genes are mainly concentrated on translation,chloroplast envelope,adenylate kinase activity,structural constituent of cell wall and ATP hydrolysis coupled proton transport.No significant KEGG differential pathway is found in leaves among different damage levels.Besides,we also analyze the pathways involved in pest response and resistance,such as tarch and sugar metabolism,plant-pathogen interactions,phenylpropanoid biosynthesis,carbon fixation in photosynthetic organisms,porphyrin and chlorophyll metabolism. |
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