Dynamic QTL mapping revealed primarily the genetic structure of photosynthetic traits in castor (Ricinus communis L.)

• Published in: Scientific reports Vol. 13; no. 1; p. 14071
• Main Authors: Huang, Guanrong, Yin, Xuegui, Lu, Jiannong, Zhang, Liuqin, Lin, Dantong, Xie, Yu, Liu, Haiyan, Liu, Chaoyu, Zuo, Jinying, Zhang, Xiaoxiao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28-08-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/208/207; 631/208/2491; 631/208/721; 631/208/729; 631/208/8; Breeding; Carbon dioxide; Chlorophyll; Efficiency; Epistasis; Gene mapping; Genetic structure; Humanities and Social Sciences; multidisciplinary; Phenotypic variations; Pleiotropy; Quantitative trait loci; Ricinus communis; Science; Science (multidisciplinary); Stomata; Stomatal conductance; Transpiration; Water use; Water use efficiency
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-41241-y

High photosynthetic efficiency is the basis of high biomass and high harvest index in castor (
Ricinus communis
L.). Understanding the genetic law of photosynthetic traits will facilitate the breeding for high photosynthetic efficiency. In this study, the dynamic QTL mapping was performed with the populations F
2
and BC
1
derived from 2 parents with significant difference in net photosynthetic rate (Pn) at 3 stages, in order to reveal the genetic structure of photosynthetic traits. In F
2
population, 26 single-locus QTLs were identified, including 3/3/1 (the QTL number at stage I/II/III, the same below), 1/2/0, 1/2/2, 1/3/1, 0/1/1, and 1/1/2 QTLs conferring Pn, water use efficiency (Wue), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO
2
concentration (Ci) and chlorophyll content (Cc), with a phenotypic variation explained (PVE) of 8.40%/8.91%/6.17%, 5.36%/31.74%/0, 7.31%/12.80%/15.15%, 1.60%/6.44%/0.02%, 0/1.10%/0.70% and 2.77%/3.96%/6.50% respectively. And 53 epistatic QTLs (31 pairs) were identified, including 2/2/5, 5/6/3, 4/4/2, 6/3/2, 3/2/0 and 4/0/0 ones conferring the above 6 traits, with a PVE of 6.52%/6.47%/19.04%, 16.72%/15.67%/14.12%, 18.57%/15.58%/7.34%, 21.72%/8.52%/7.13%, 13.33%/4.94%/0 and 7.84%/0/0 respectively. The QTL mapping results in BC
1
population were consistent with those in F
2
population, except fewer QTLs detected. Most QTLs identified were minor-effect ones, only a few were main-effect ones (PVE > 10%), focused on 2 traits, Wue and Tr, such as
qWue1.1
,
qWue1.2
,
FqTr1.1, FqTr6, BqWue1.1
and
BqTr3
; The epistatic effects, especially those related to the dominance effects were the main genetic component of photosynthetic traits, and all the epistatic QTLs had no single-locus effects except
qPn1.2
,
FqGs1.2, FqCi1.2
and
qCc3.2
; The detected QTLs underlying each trait varied at different stages except stable QTLs
qGs1.1
, detected at 3 stages,
qWue2
,
qTr1.2
and
qCc3.2
, detected at 2 stages; 6 co-located QTLs were identified, each of which conferring 2–5 different traits, demonstrated the gene pleiotropy between photosynthetic traits; 2 QTL clusters, located within the marker intervals RCM1842-RCM1335 and RCM523-RCM83, contained 15/5 (F
2
/BC
1
) and 4/4 (F
2
/BC
1
) QTLs conferring multiple traits, including co-located QTLs and main-effect QTLs. The above results provided new insights into the genetic structure of photosynthetic traits and important references for the high photosynthetic efficiency breeding in castor plant.