Essay --

The main questions addressed in this research were based on the Medicago Truncatula- Sinorhizobium symbiosis that form indeterminate (non-reproducing bacteria) nodules. a) to see whether M. truncatula displays partner choice in picking the most efficient rhizobia between nitrogen fixing and non fixing bacteria in both pre- infection and post- infection scenarios. b) the authors also wanted to see if legumes can alter their allocation of carbon photosyntates to each nodule depending on how efficient the rhizobia is in each nodule. Authors of this article did this research because this symbiotic relationship is widely studied, but all the research done so far have been on determinate (bacteria is able to reproduce) nodules1 rather than indeterminate nodules. In previous research it was found that determinate nodules show both partner choice and allocation differentiation between efficient and non- efficient rhizobia. Answer2: Authors hypothesized that in Medicago Truncatula- Sinorhizobium that form indeterminate nodules will show partner choice in both pre infection and post infection scenarios and select for the most efficient rhizobia partner. They also hypothesized that the legume will show differential allocation of carbon photosyntates in each nodule depending on the number of nitrogen fixing and non fixing rhizobia in each nodule. Answer3: Figure # What method(s) gave this data? What do these data show? Figure1a The authors performed a split- root experiment to obtain data based on three different parameters and then used MANOVA analyses to compare the three parameters used in the experiment. They used Post hoc on all the measurements to use it to graph the differences. ANOVA to compare the mean of the two strains used... ...thors hypothesis. However, they were not able to show difference in the resource allocation to each nodule depending on the efficiency of bacteria in each nodule. Therefore they concluded that sanctioning is not present is not present in all legume unlike the partner choice. Answer5: The authors think that the discrepancy in the results of the previous researches and theirs regarding allocations by the legume to nitrogen fixing and non- fixing bacteria is that the authors used M. truncatula- sinorhizobium indeterminate nodules whereas other researchers used either soybean or yellow bush lupin determinate nodules. Since this is the first time such model is presented I think that there should be more researches focusing only the sanctions by legumes to the bacteria to better understand the symbiosis between M. truncatula - Sinorhizobium and sanctions in general.