**5. Conclusions**

In our work, we demonstrated changes in the abundance and diversified expression of the epitopes of the AGP genes encoding FLA, EXT and EXT-like receptor kinases in the leaves of *B. distachyon* in response to temperature stress.

The main findings are as follows:

1. An increase in the JIM8 signal in the walls of phloem cells at 40 ◦C and a decrease at 4 ◦C.

2. An increase in the abundance of the LM2 epitope in the leaves of plants that had been subjected to the high temperature.

3. A decrease in the JIM16 signal intensity at 4 and 40 ◦C.

4. The upregulation of some *FLA*, *EXT* and *EXT-like* receptor *kinases* genes in response to temperature stress (4 and 40 ◦C).

5. The expression of the *PERK EXT* gene *Bradi3g31967* only in the leaves under low and high temperature stress.

To summarise, our results extend the knowledge about the presence of these epitopes in connection with temperature stress in *B. distachyon*. A precise dissection of the functions of AGP and EXT in response to abiotic stresses and to temperature stress, among others, requires the use of specific mutants whose availability is still limited. However, recent developments in the site-directed mutagenesis techniques such as CRISPR/Cas9 should allow the selective targeting of these genes, which may be helpful to better understand their roles.

**Author Contributions:** Conceptualisation, A.P., A.B.; methodology, A.P., A.B., K.S., K.G.-J.; validation, A.P., K.S., A.B.; formal analysis, A.P., K.S., A.B.; investigation, A.P., K.S., A.B.; resources, R.H., E.K.; data curation, A.P., A.B., K.S.; writing—original draft preparation, A.P., A.B., K.S., E.K.; writing—review and editing, A.P., A.B., K.S., E.K., R.H.; visualisation, A.P.; supervision, A.B., R.H.; funding acquisition, R.H., E.K.

**Funding:** This research was funded by the National Science Centre Poland (grant DEC-2014/14/M/NZ2/00519).

**Conflicts of Interest:** The authors declare no conflict of interest.
