Figure 4: Positional cloning of PTB1.
From: Natural variation in PTB1 regulates rice seed setting rate by controlling pollen tube growth
(a) PTB1 was first mapped to the short arm of chromosome 5 using a bulked segregation analysis. (b) PTB1 was then delimited to a genetic region flanked with the markers RM413 and RM405 and co-segregated with RM592 in a small population (n=100). (c) PTB1 was finally narrowed down to a 72-kb region between markers RL33 and RD19 and co-segregated with Rl60 in a large population (n=2,382). (d) In total, nine genes were predicted within the 72-kb region. (e) Sequencing revealed a 470-nt deletion in the coding region of the mutant LOC_Os05g05280 gene; this deletion resulted in a premature termination of the predicted open reading frame. (f) PCR confirmation of the corresponding deletions (arrowed) in some F2 sterile plants (n>50). (g) RT–PCR confirmation of the corresponding deletions (arrowed) in some F2 sterile plants (n>50).
