Biochemistry of Nectar Proteins

  title={Biochemistry of Nectar Proteins},
  author={Sanggyun Park and Robert W. Thornburg},
  journal={Journal of Plant Biology},
Floral nectar is a rich concoction of sugars, amino acids, vitamins, lipids, and other ingredients that is usually secreted at the base of a flower. Nectar is offered freely to attract large numbers of visiting pollinators to the flower. These visiting pollinators then transfer pollen between flowers, completing the plant’s sexual cycle to produce seeds. However, in addition to transferring pollen, visiting pollinators also transfer microorganisms between flowers when they drink nectar. Because… 

Sugary Exudates in Plant Pollination

Floral nectar evolved rapidly when the transition from naked ovule to closed carpel was completed and the pollination drops were no longer available as a food resource for insects.

Nectar Secretion: Its Ecological Context and Physiological Regulation

This work recommends the use of contemporary “omics” techniques in comparative approaches to understand how plants synthesize and secrete nectar.

Nectar Microbial Diversity and Changes Associated with Environmental Exposure

The results suggest that floral nectars in different plant species do contain a distinct microbiome and the individual flower microbial community diversity may be affected by floral nectar composition, insect visitation and other environmental factors.

Beyond nectar sweetness: the hidden ecological role of non‐protein amino acids in nectar

It is proposed that non‐protein amino acids in nectar may contribute to the plant–insect network of interactions in a number of ways: by affecting the physiology of the nervous system of the insect, regulating nectar intake through phagostimulation and promoting muscle function during flight.

The Production and Protection of Nectars

Little is known about how nectaries are formed, where nectar components are produced and how nectar flow is controlled, but more studies are required to understand the genetic control of nectary formation and the mechanisms by which plants control nectarflow and composition.

' s personal copy Nectar : generation , regulation and ecological functions

Nectar contains water, sugars and amino acids to attract pollinators and defenders and is protected from nectar robbers and microorganisms by secondary compounds and antimicrobial proteins. Floral

Plant secondary metabolites in nectar: impacts on pollinators and ecological functions

Evidence from recent literature that supports selection for secondary metabolites in floral nectar as an adaptation that drives the co-evolution between plants and their pollinators is synthesised.

Natural variation in floral nectar proteins of two Nicotiana attenuata accessions

Next-generation sequencing and advanced proteomics are used to profile FN proteins in the opportunistic outcrossing wild tobacco, Nicotiana attenuata, and suggest that nectar chemistry may have a complex function in plant-pollinator-microbe interactions.

Nectar chemistry is tailored for both attraction of mutualists and protection from exploiters

The chemical composition of both FNs and EFNs is reviewed and it is found that nectar composition appears tailored to fulfil these ambivalent roles: in attraction and the protection of nectar.



A major function of the tobacco floral nectary is defense against microbial attack

The characterized major nectar protein from ornamental tobacco as a superoxide dismutase that functions to generate high levels of hydrogen peroxide in nectar indicates that the floral nectary gland can have specific functions in plant defense.

Nectarin I is a novel, soluble germin-like protein expressed in the nectar of Nicotiana sp.

A limited number of proteins secreted into the nectar of tobacco plants are identified and Nectarin I is the most highly expressed nectar protein and has a monomer molecular mass of 29 kDa.

The nectary as the primary site of infection by Erwinia amylovora (Burr.) Winslow et al.: a mini review

The ecology and infection biology of Erwinia amylovora on floral surfaces and in floral tissues is reviewed to review the interrelationships of free moisture, nectar sugar concentration, ovary water potential, fine-structural characteristics of nectary versus the disease incidence and severity.

Tobacco Nectarin III is a Bifunctional Enzyme with Monodehydroascorbate Reductase and Carbonic Anhydrase Activities

RT-PCR based expression analyses demonstrated that NEC3 transcript is expressed throughout nectary development as well as in other floral organs, and a proposed function in the maintenance of pH and oxidative balance in nectar is discussed.

The nectary-specific pattern of expression of the tobacco Nectarin I promoter is regulated by multiple promoter elements†

Analysis in transgenic plants revealed that the nectary-specific expression is the result of multiple promoter elements and suggests that nectar secretion and flower opening may be coordinately regulated.

Tobacco Nectaries Express a Novel NADPH Oxidase Implicated in the Defense of Floral Reproductive Tissues against Microorganisms1[OA]

In situ hybridization studies indicated that the NADPH oxidase was expressed in the early stages of flower development although superoxide was generated at later stages (after Stage 10), implicating posttranslational regulation of the NAD PH oxidase in the nectary.

Lectin and alliinase are the predominant proteins in nectar from leek (Allium porrum L.) flowers

Honey produced by bees foraging on flowering leek plants still contains biologically active lectin and alliinase, however, the levels of both proteins are strongly reduced as compared to those in the original nectar.

Germin, a protein marker of early plant development, is an oxalate oxidase.

Tobacco Nectarin V Is a Flavin-Containing Berberine Bridge Enzyme-Like Protein with Glucose Oxidase Activity

RT-PCR-based expression analyses showed that nec5 expression is limited exclusively to the nectary gland during late stages of floral development, and in-gel assays demonstrated that NEC5 contains a covalently linked flavin, and it possesses glucose oxidase activity.

Tobacco Nectarin I

Nectarin I, a protein that accumulates in the nectar of Nicotiana sp., was determined to contain superoxide dismutase activity by colorimetric and in-gel assays. This activity was found to be