Sucrose rather than GA transported by AtSWEET13 and AtSWEET14 supports pollen fitness at late anther development stages

Abstract

Both sugar and hormone gibberellin (GA) are essential for anther-enclosed pollen development and thus for plant productivity in flowering plants. Arabidopsis (Arabidopsis thaliana) AtSWEET13 and AtSWEET14, which are expressed in anthers and associated with seed yield, transport both sucrose and GA. However, it is still unclear which substrate transported by them directly affects anther development and seed yield. Histochemical staining, cross-sectioning and microscopy imaging techniques were used to investigate and interpret the phenotypes of AtSWEET13 and AtSWEET14 double mutant during anther development. Genetic complementation of atsweet13;14 using AtSWEET9 that transports sucrose but not GA was conducted to test the substrate preference relevant to the biological process. The loss of AtSWEET13 and AtSWEET14 resulted in reduced pollen viability and therefore decreased pollen germination. AtSWEET9 fully rescued the defects in pollen fertility of atsweet13;14, indicating AtSWEET13/14 mediated sucrose rather than GA is essential to pollen fertility. AtSWEET13 and AtSWEET14 mainly function at the anther wall during late anther development stages and are likely responsible for sucrose efflux into locules to support pollen development to maturation, which is vital for subsequent pollen viability and germination.

A 163‐bp insertion in the Capana10g000198 encoding a MYB transcription factor causes male sterility in pepper (Capsicum annuum L.)

“…Such results may derive from false‐positive caused by the low expression levels of CaMYB33 in the MF anthers, or the expression of CaMYB33 may be partially regulated by Capana10g000198 through a complicated positive feedback loop as in the feedback regulation of DYT1 (Cui et al., 2016). For the remaining differently expressed pepper GMS genes, including the CaIPE1 , CaMEE48 , CaQRT3 and CaSWEET14 , all of their Arabidopsis homologs have been reported to be associated with tapetum and/or pollen wall development (Chen et al., 2017; Dobritsa et al., 2011; Shi et al., 2021; Wang et al., 2022). At the transcription level, the AtQRT3 and AtMEE48 have been found to be downregulated in myb80 mutant, and the AtSWEET14 has been found to be upregulated in myb80 / MYB80 functional complementation lines in Arabidopsis (Huy et al., 2011; Zhu et al., 2008), while whether the CaIPE1 is regulated by the Capana10g000198 is still largely unknown.…”

Identification and expression analysis of pineapple sugar transporters reveal their role in the development and environmental response

“…Although SWEET transporters were initially found in plants, their homologs have been found in many other organisms. In addition to the transport of mono- and di-saccharides, SWEETs have been implicated in the transport of phytohormones such as gibberellin (GA) ( Chen et al., 2015 ; Kanno et al., 2016 ; Wang et al., 2022 ; Xue et al., 2022 ).…”