Trading amino acids at the aphid– Buchnera symbiotic interface (2024)

FAQs

What is the symbiotic relationship between aphids and Buchnera? ›

The bacteria are transmitted vertically via the aphid ovary, and the association is obligate for both partners: Bacteria-free aphids grow poorly and produce few or no offspring, and Buchnera are both unknown apart from aphids and apparently unculturable. The symbiosis has a nutritional basis.

Plant sap is such a limited food source for the aphid because it predominantly contains four amino acids—glutamine, glutamate, asparagine and aspartate—which serve as the primary nitrogen source for the aphid. Plant roots synthesize these amino acids to transport nitrogen compounds, which they take up from the soil.

In a model nutritional mutualism, aphids harbor the endosymbiont, Buchnera, within specialized bacteriocyte cells. Buchnera synthesizes essential amino acids (EAAs) and vitamins for their host, which are lacking from the aphid's plant sap diet.

Aphids have an obligate association with the bacterium Buchnera aphidicola (the primary symbiont) that has been shown to contribute directly to aphid fitness.

Mutualism is advantageous for both partners; aphids provide ants with sugar-rich honeydew as a source of food and the ants protect the aphids against various natural enemies and improve the hygiene of the aphid colony.

Ladybird beetles are natural enemies of aphids, insects that kill plants. Ladybugs can control insect pests through natural predation. Aphids are tiny insect pests. They suck the sap from many types of plants such as vegetables, fruits, flowers, and trees.

Short Answer

Among the five tested organisms, the highest number of amino acids common to aphids was found in Ustilago (a fungus).

Aphids get most of their nitrogen and nutrients from free amino acids in phloem sap, and the concentration and composition of amino acids in phloem are essential indicators of nutritional quality for aphids [1, 3].

Nine essential amino acids biosynthesis leading to lysine (Lys), methionine (Met),threonine (Thr), phenylalanine (Phe), tryptophan (Trp), valine (Val), isoleucine (Ile), leucine (Leu), and histidine (His) in plants.

Neem oil, insecticidal soaps, and horticultural oils are effective against aphids, but these substances need to come into contact with the aphids in order to work. Be sure to follow the application instructions provided on the packaging.

Are aphids helpful or harmful? ›

Aphids in small numbers do minimal damage. But these insects are considered to be some of the most destructive agricultural pests in temperate regions. Infestations of aphids have been known to occur, causing discoloration, spotting, or puckering of leaves.

They have sucking mouthparts and feed exclusively on plant sap. Aphids feed on stems, leaves, and even roots! They reproduce rapidly to form colonies or clumps, particularly on new growth.

Pea aphid possesses Buchnera aphidicola as an obligate symbiont. The pea aphid–Buchnera symbiosis is a nutritional symbiosis because aphids with an unbalanced diet of plant phloem sap are nutritionally dependent on their Buchnera symbiont for acquiring essential amino acids (Douglas, 1998).

Some bacteria that grow on leaf surfaces, such as Pseudomonas syringae, can infect and kill aphids, making them potentially useful in the biological control of pest aphids. However, only one aphid species, the pea aphid (Acyrthosiphon pisum), has been tested for infection by P. syringae.

At the same time, many aphids release an alarm pheromone that for many species consists of the sesquiterpene hydrocarbon (E)-β-farnesene (Eβf), which causes other aphids in the vicinity to stop feeding and to move away (1). Eβf can also increase the proportion of aphid progeny that are alate (winged) (2).

Aphids are phloem sap-feeding insects and most cultivated plant species are hosts of one or more aphid species. Aphids damage plants mainly by plant nutrient withdrawal, by virus transmission, and via indirect reduction of photosynthesis due to sooty mould growing in their excreta.

True bugs have piercing-sucking mouthparts (Fig. 1) and belong to the order Hemiptera and suborder Heteroptera. There are more than 38,000 species of true bugs, and are most closely related to aphids, cicadas, and leaf hoppers.

The milkweed aphids eat the plant and produce a sugary substance called 'honeydew' that the ants 'milk' from the aphid's anus. The ant benefits the aphid by protecting it from predators like ladybugs. Note the tiny 'fly-like' insect at the top of the leaf.