Fig 1.
Salt glands of the mangrove species Avicennia officinalis.
(A) Transverse section of leaf showing the adaxial (upper) epidermal layer with two salt glands (arrows). (B) Secretion (scn) above the salt gland (sg) can be observed from the top view of the adaxial epidermal layer. (C) The salt gland-enriched epidermal peels (*) as indicated by the right brace in (A) were obtained from the leaves for subsequent protein extraction and downstream proteomic analysis. Scale bars: 20μm (A), 100μm (B), 1cm (C).
Fig 2.
Identification and analysis of salt gland-enriched proteome.
(A) The experimental approach for generation of a salt gland-enriched proteome through the use of two distinct set of samples: total proteins from the adaxial (upper) epidermal peels (with salt glands) and from the mesophyll tissues (no salt glands). (B) The number of proteins that are identified in salt gland-enriched epidermal peels from three biological replicates is presented in the Venn diagram. Identified proteins from the salt gland-enriched tissues that were present in all the three biological replicates were grouped according to the number of unique peptides (C) and % sequence coverage (D). The identified proteins (D) were classified according to the protein’s sequence coverage.
Table 1.
Number of proteins identified from adaxial (upper) epidermal peels and mesophyll tissues of the leaves of A. officinalis.
Fig 3.
GO annotation of proteins identified in salt gland-enriched tissues of A. officinalis.
A total of 1032 proteins were analysed. The proteins were classified based on GO for (A) biological process, cellular component and (B) molecular function. The major subcategories of molecular function (B) are shown in more detail on the left and right sides below the corresponding subcategories.
Table 2.
Selected list of proteins identified from salt gland-enriched epidermal tissues of A. officinalis.
These proteins are identified in the epidermal tissues but not in the mesophyll tissues of A. officinalis and only those that are present in two out of the three biological replicates are selected for further anlaysis. The full list of proteins is presented in S8 Table.
Fig 4.
Schematic diagram of salt gland cell showing predicted cellular localization of selected list of 10 annotated proteins identified from salt gland-enriched epidermal tissues of A. officinalis.
The selected proteins were classified based on GO for cellular component and Swissprot ID of the proteins are included in parentheses.