Expression divergence of FRUITFULL homeologs enhanced pod shatter resistance in Brassica napus

Abstract

ABSTRACT. To improve pod shatter resistance in the important oilseed crop Brassica napus, the phenotypic diversity of B. napus was tested using 80 B. napus varieties for pod shatter resistance by a random impact test. Among these varieties, R1-1 was identified as resistant, while R2, 8908B was susceptible to shatter. To understand the molecular basis for this phenotypic difference based on the candidate gene approach, B. napus FRUITFULL (FUL) homologs were identified and characterized. Two FUL loci in the A and C genomes of B. napus were identified. In the susceptible variety, both BnaA.FUL and BnaC.FUL were expressed in the same tissues. However, the expression level of BnaC.FUL differed in varieties with different pod shatter resistance. In the most resistant variety, R1-1, only BnaA.FUL was expressed, while BnaC.FUL was silenced. Therefore, the functional divergence and differing expression of BnaX.FUL homeologs may significantly affect phenotypic variation, which is an important consequence of allopolyploid evolution. This expression level divergence may be useful for selecting pod shatter resistant lines through marker-assisted selection in B. napus-breeding programs.

BnDGAT1s Function Similarly in Oil Deposition and Are Expressed with Uniform Patterns in Tissues of Brassica napus

“…In allopolyploid cotton, the expression of two alcohol dehydrogenase AdhA homoeologs varied in response to cold, dark, or submergence stress ( Liu and Adams, 2007 ). Similar expression changes were also found in peroxidase , FLC and FRUITFULL genes in B. napus ( Pires et al, 2004 ; Zhao et al, 2009 ; Peng et al, 2015 , respectively). Gene silencing of some homoeologs is also common in polyploids, occurring in wheat, cotton and B. napus ( Adams, 2007 ; Gaeta et al, 2007 ).…”

“…The expression of duplicated genes may also become diversified in different tissues ( Pires et al, 2004 ; Federico et al, 2006 ; Zhao et al, 2009 ; Peng et al, 2015 ). We surveyed the expression of BnDGAT1s in eight tissues from four lines with different expression patterns in seeds.…”

BnLATE, a Cys2/His2-Type Zinc-Finger Protein, Enhances Silique Shattering Resistance by Negatively Regulating Lignin Accumulation in the Silique Walls of Brassica napus

“…These results were further proved to be reliable at the lignin content measured in the silique walls of 73290 at 12, 24, 36, 48, and 60 DAP (Fig 5C). Furthermore, the silique shattering resistance index (SRI) was measured in mature siliques of 73290 using a previously described random impact test [28]. As shown in Fig 5D, the SRI of 73290 was as high as 0.78 and 0.75 at 252 and 280 revolutions per minute (rpm), respectively, and under the extreme rpm (313) still with 0.35.…”

“…Mature siliques of 73290 were collected for measurement of silique shattering resistance by a random impact test [28]. Briefly, 20 siliques were reserved in an air-tighten bag overnight after incubation at 80°C for 30 minutes to equilibrate moisture, then continuous record cracked siliques after 2-min intervals of shaking for five times on a shaker with 12 steel balls (diameter 13 mm) at 252, 280 and 313 revolutions per minute (rpm) in a cylindrical container, which was 19 cm in diameter and 14 cm in height.…”

Homoeologs: What Are They and How Do We Infer Them?

“…Additionally, we can study the functional divergence of homoeologs on polyploidization, particularly in terms of expression (reviewed in 2 , 8 , 10 , 11 , 12 , 13 ), epigenetic patterns (reviewed in 8 , 12 ), alternative splicing [14] , and diploidization (reviewed in [8] ). From a crop improvement viewpoint, identifying homoeologs that may have been functionally conserved is important for elucidating or engineering the genetic basis for traits of interest 15 , 16 .…”