Phytochemical screening, GC-MS profiling of invasive cocklebur (Xanthium strumarium)-insect-pathogen interaction and simulated volatile chemical signaling at Northeast China

Abstract

Invasive cocklebur (Xanthium strumarium) is characterized by its excellent genetic 10 and ecological plasticity, ability to spread in agriculture crops. There is a dire need to locate 11 useful management strategies to control this invasive weed at diversified latitudinal gradients. In 12 ecology, there is weak evidence that the damage caused by the natural enemy varies with 13 latitudes. Therefore, we investigated this evidence with the help of transect quadratic ecological 14 sampling method which was conducted randomly at ten different sites of Northeast China. 15Overall, significantly high infestation of gall-forming insect (Epiblema strenuana) was observed 16 on Xanthium leaves (21.16%) at 41.51279°N, followed by 40.2241°N latitude. Similarly, there 17 was a significantly high abundance of Epiblema infestation (7.3) with high damage (3.88%) at 18 41.51279°N and 40.12749°N latitude. Likewise, the fungal abundance (5.6) of rust i.e. Puccinia 19 xanthii (presenting 16.23% attack) was dominated significantly at 41.51279°N. Hence, high 20 pathogen infection rate (8.97%) was detected at 40.2241 o N. On the other hand growth 21 parameters, i.e. plant height (cm), stem diameter (mm) vary with latitude and longitudinal trends. 22 In our experiment, of plant natural enemy interaction provides the evidence-based indication the 23 Epiblema abundance, was diversified at 41.51279 o N, and P. xanthii infection was most frequent 24 at 40.22411°N latitudes. This study provides an evidence-based indication that natural enemy 25 pressure varies with latitude, however this investigations gave valuable information that insect 26 and phytopathological fungus having biological control potential against Xanthium strumarium 27 invasive weed. Secondly, phytochemical qualitative and chemical signaling through Gas 28 Chromatography-mass spectrometry (GC-MS) executed the presence of flavonoids, phenols, 29 saponins, alkaloids, terpenoids, nitrogen (N), sulpher (S), silicon (Si) containing compounds in 30 both treated and controlled leaves that defend against Puccinia xanthii. Fascinatingly, all X. 31 strumarium populations collected from different latitudes possess similar compositions. In 32 interaction mechanism, plant known to omit volatile organic compounds in response to attack of 33 natural herbivores. The leave chemical profiling suggested that the influence of fungus attack on 34 invasive weed brought different changes in chemical infrastructure of leave and these chemicals 35 also play a vital role in the food web. After attack of these biological control agents, plants 36 exhibits passionate compound reprogramming within the leaf naturally that act upon in defense 37 systems. 38 Author summary 39 • The study was conducted to observe the environmental impact on the trend of insect, 40 invasive weed and pathogens. 41 • There was a significant dominance of gall-forming insect on invasive Xanthium weed at 42 all locations. 43 • Puccinia xanthii infected more than 16% plantation 44 • Plant growth had significant variation at variou...