Comparative Analysis of Amino Acid and Sugar Profiles in Broad Beans (Vicia faba) and Alfalfa (Medicago sativa): Implications for Suitability as Host Plants for Sap-sucking Insects Like Pea Aphids

Pea aphids need amino acids for growth and reproduction, and sugars for energy. Broad beans (Vicia faba) and alfalfa (Medicago sativa), their common host plants, may offer different amino acid and sugar profiles, which can impact aphid rearing conditions. Thus, this study examined the quantity of these two key nutritional factors in the leaf samples of broad beans and alfalfa. The study was conducted at the college of plant protection, Northwest A& F University, Yangling, China. Linear Ion Trap mass spectrometer with Liquid chromatography separations were used to analyze the two nutrients in the leaf samples. The results showed that V. faba had higher concentrations of certain amino acids compared to M. sativa. In M. sativa, the most abundant amino acids were non-essential, including asparagine (36.03%), glutamic acid (17.37%), and serine (11.92%). Similarly, in V. faba, the most abundant amino acids were also non-essential, including asparagine (60%), tyrosine (7.08%), and glutamic acid (3.91%). The most abundant essential amino acids in M. sativa were threonine (31.28%), leucine (16.1%), and valine (15.72%), while in V. faba, they were histidine (48.4%), lysine (14.04%), and valine (9.7%). Essential amino acids contributed 9.65% to the total amount of amino acids in M. sativa and 12.35% in V. faba. The most varied essential amino acids in the two plants were histidine, lysine, and phenylalanine. The total concentration of fructose, glucose, and sucrose differed significantly between the two plants, with individual sugars in V. faba being significantly higher than those in M. sativa. Moreover, the analysis revealed that both total amino acids and sugars were significantly higher in V. faba than in M. sativa. These findings suggest that the broad bean may be a more suitable host plant for rearing pea aphids than alfalfa.