A minor QTL, SG3, encoding an R2R3-MYB protein, negatively controls grain length in rice
Key message SG3 , an R2R3 MYB protein coding gene that tightly linked to a major QTL GS3 , negatively regulates grain length while dependent on the status of GS3 in rice. It is often very difficult to isolate a minor QTL that is closely linked to a major QTL in rice. In this study, we focused on the...
Saved in:
Published in | Theoretical and applied genetics Vol. 133; no. 8; pp. 2387 - 2399 |
---|---|
Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.08.2020
Springer Springer Nature B.V |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Key message
SG3
, an R2R3 MYB protein coding gene that tightly linked to a major QTL
GS3
, negatively regulates grain length while dependent on the status of
GS3
in rice.
It is often very difficult to isolate a minor QTL that is closely linked to a major QTL in rice. In this study, we focused on the isolation of a minor grain length QTL,
small grain 3
(
SG3
), which is closely linked to the major QTL
grain size 3
(
GS3
). The genetic effect of
SG3
on grain length was dependent on
GS3
status. Its genetic effect was larger in the presence of nonfunctional
sg3
than functional
SG3
. A large number of near-isogenic F2 plants in which
GS3
was fixed with nonfunctional alleles were developed to clone
SG3
. A gene encoding an R2R3 MYB domain transcriptional regulator was identified as the candidate gene for
SG3
.
SG3
overexpression and knockdown plants showed shortened and elongated grains, respectively, which demonstrated that
SG3
acts as a negative regulator of grain length.
SG3
was preferentially expressed in panicles after flowering, and
SG3
acted as a transcription activator. Comparative sequencing analysis identified a 12-bp insertion in the third exon of NYZ that led to a frameshift and resulted in a premature stop codon. The insertion/deletion was associated with grain length in the presence of functional
GS3
in the
indica
subspecies.
SG3
and
GS3
were frequently in coupling phase in
indica
rice, making them good targets for the breeding of cultivars with short or long grains. The isolation of the
SG3
MYB gene provides new gene resource and contributes to the regulatory network of grain length in rice. |
---|---|
ISSN: | 0040-5752 1432-2242 |
DOI: | 10.1007/s00122-020-03606-z |