Study On The Relationship Of Source-sink Between Horn Gall And Its Host Plant Rhus Chinensis

Horn gall caused formation of leaf wing metamorphosis in the Rhus chinensis Mill by Schlechtendalia chinensis Bell feeding on the leaf wing position of R.chinensis.Horn gall are widely used in various industries because of the rich tannic acid.Horn gall is one of the most widely distributed and the largest gallnut,which plays a decisive role in the production of gallnut.The development of horn gall is carried out in the synergistic balance between the S.chinensis and the host plant R.chinensis.The mechanism is very complicated.In the current study,we selected the distribution and segmentation of photosynthetic products as the research target,and comprehensively applied field survey,tracing mark,removal leaflet,amino acid nutrient determination and molecular expression analysis methods to explore the source-sink relationship between the R.chinensis and the auxe of horn gall.Horn gall is the nutrient sink,and the auxe of it is mainly supplied by the leaflets of the plant.Horn gall and the leaflets of the compound leaf constituted source-sink relations.At the early rapid auxe stage of horn gall,the upper and lower branches of the compound leaf were ring cutting and in the later period,the volume of the control is 16.53 times and 14.02 times more than that of the control.The volume of the control S.chinensis increased by 13.64 times and 16.39 times respectively,the difference is not significant.Removing the source leaves at the early rapid development stage,the development of the horn gall volume in the later stage was significantly slowed down.The anaphase treatment and the control gall add the volume by2.21 times and 16.34 times respectively.The difference between the two is significant.The formation of horn gall has promoting effect on the leaflets growth of the host R.chinensis,this volume was positively correlated with horn gall promoting,and then it can improve the supply capacity of the source of nutrition.The migration of natural and artificial hanging bags are two important ways to make up galls.Investigation and statistical analysis of the two ways on R.chinensis with galls and without galls showed that:The number of lateral branches,the number of tips of branches,the number of leaves and the total area of leaflets were significantly higher than those R.chinensis without galls.At the same time,there was a significant difference in the total area of leaflets with multiple trees that were manually hung in insect bags and caused by natural migration.It was demonstrated that the formation of S.chinensis had a promoting effect on the growth of the leaves of the host plant,and this promotion was positively related to the horn gall volume.Artificially hanging insect bags can effectively stimulate R.chinesis growth potential and increase yield.The principal component analysis showed that the contribution of the number of shoots and the number of compound leaves was the largest.There is a competition and coordination mechanism in the source-sink nutrition ralation among horn galls,and the relationship can be changed in certain conditions.Horn gall and S.chinensis is the main object of R.chinensis leaf assimilates transportation and direction.The¹³CO₂ were feedinged and injected at different positions of the compound leaves at the branches,and the ¹³C glucose were injected in horn gall.The results showed that the carbon source of photosynthetic carbon reaction was distributed on the compound leaf of R.chinensis,The ¹³C tracer shows that the S.chinensis and horn gall magnification are always the main distribution objects and direction of the photosynthetic carbon source of the apical leaflet,and the source-sink unit is composed of the leaves of R.chinensis,the horn gall is the sink of nutrient import,and the S.chinensis magnification is more that the greatest beneficiary of photosynthetic carbon allocation.It is the first priority to supply specific“sink”.It is concluded that the S.chinensis are operators that drive R.chinensis of times to develop into nutrient sink with combining the key role of S.chinensis in the continuous development of horn gall.The determination of the adjacent horn galls were injected ¹³C glucose showed that the delta ¹³C of the horn gall and S.chinensis were enriched in the unlabeled horn galls,among which the abundance of S.chinensis was the largest,followed by the horn gall.There is a coordinated flow of nutrients between different horn galls.This nutrient flow may be related to the feeding aspiration and the structure of horn gall.The honeydew components of S.chinensis can be transmitted to the adjacent horn galls and leaves,indicating that the nutrition transmission is not only the one-way flow of leaf to horn gall,but the source-sink relationship between S.chinensis and R.chinensis can be changed under certain conditions.Horn gall have a significant effect on the changes in the amino acid content of the host R.chinensis and there is a conversion of source-sink relationship during the growth period.In the different auxe period of horn gall,the amino acid composition of the tested material was the same,but the content of amino acid nutrition of the host plant changed.The hydrolysis and free amino acids in horn gall were lower than that of the leaves at the early auxe stage of it.As the auxe to the middle and late stages,the hydrolysis of horn gall and the free amino acid level exceeded the host R.chinensis leaf,indicating that after S.chinensis stimulated the host plant,the content of the amino acid in R.chinensis leaf was changed by physiological metabolism.In addition,the nutrient source is gradually formed,which can be allocated to horn gall to meet the auxe needs of the angular times.The results support the source-sink hypothesis of the gall,and at the later stage,with the increase of the amino acid nutrition,it can also transmit nutrition to the adjacent leaves.The increase of the content of this amino acid is consistent with the increasing trend of the individual number of S.chinensis and the volume of horn gall.The rapid increase in the free amino acid content of the gall and adjacent leaves reflects the increase of the resistance to the aphids with the number of aphids,and further reflects the balance between the feeding of the aphid and the defense of R.chinensis.Horn gall have highly expressed active enzymes of assimilate transport and sucrose synthesis and transfer at the molecular level,and it have a powerful sink,Illumina technology was used to deeply sequence horn gall and R.chinensis leaves to obtain 112,543 Unigenes with an average length of 1133 bp.76,949 Unigenes were annotated,accounting for a total of68.37%.Systematic clustering found that horn gall and leaves were enriched in starch and sugar metabolism and photosynthetic pathways.The photosynthetic system related genes and Rubisco transcripts of horn gall are not high,but the increase of CO2 produced by S.chinensis can increase the net photosynthetic rate of insects and make up for the deficiency of horn gall photosynthesis.The activity of sucrose synthetase,pyrophosphate,1,6-two phosphate fructose transferase?PFP?and sucrose synthetase?SPS?was highly expressed in the main assimilates of the horned fold,indicating that the horn gall is a powerful ability to absorb and coordinate the transportation and assimilation of various sources from the nutrient sink.