Multigene families of
CKX
genes encode cytokinin oxidase/dehydrogenase proteins (CKX), which regulate cytokinin content in organs of developing plants. It has already been documented that some of them play important roles in plant productivity. The presented research is the first step of comprehensive characterization of the bread wheat
TaCKX
gene family with the goal to select genes determining yield-related traits. The specificity of expression patterns of fifteen formerly annotated members of the
TaCKX
family was tested in different organs during wheat development. Based on this, the genes were assigned to four groups:
TaCKX10
,
TaCKX5
and
TaCKX4
, highly specific to leaves;
TaCKX3
,
TaCKX6
and
TaCKX11
, expressed in various levels through all the organs tested;
TaCKX1
,
TaCKX2
.
3
,
TaCKX2
.
2
,
TaCKX2
.
1
,
TaCKX2
.
4
and
TaCKX2
.
5
specific to developing spikes and inflorescences;
TaCKX9
,
TaCKX8
and
TaCKX7
, highly specific to roots. Amplification products of tested genes were mapped to the chromosomes of the A, B or D genome using
T
.
aestivum
Ensembl Plants. Based on analysis of
TaCKX
transcripts as well as encoded amino acids in
T
.
aestivum
and
Hordeum vulgare
the number of
CKX
genes in wheat was limited to 11 and new numbering of selected
TaCKX
genes was proposed. Moreover, we found that there were developmental differences in expression of
TaCKX
in the first and the second spike and expression of some of the genes was daily time dependent. A very high and significant correlation was found between expression levels of
TaCKX7
and
TaCKX9
, genes specific to seedling roots,
TaCKX1
,
TaCKX2
.
1
and
TaCKX2
.
2
, specific to developing spikes, and the group of
TaCKX3
,
4
,
5
,
6
,
10
and
11
, highly expressed in leaves and other organs. The genes also co-operated among organs and were included in two groups representing younger or maturating stages of developing plants. The first group was represented by seedling roots, leaves from 4-week old plants, inflorescences and 0 DAP spikes; the...
