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Physiological and genetic attributes of an acetolactate synthase resistant shattercane (Sorghum bicolor (L.) Moench) biotype
Abstract
Shattercane seeds were collected in 1992 from 16 fields in southeastern and south-central Nebraska treated three consecutive years with primisulfuron. A single resistant plant was found in greenhouse evaluations of 30,001 plants. Absorption, translocation, and metabolism experiments comparing acetolactate synthase (ALS)-susceptible forage sorghum (ROX) to resistant shattercane (RS) were conducted. ROX had 10% and 12% greater $\sp{14}$C absorption than RS 24 and 96 h after treatment, respectively. Over time, absorption of $\sp{14}$C increased, while $\sp{14}$C translocation from treated leaf to shoots and roots remained constant for ROX and RS. Unmetabolized primisulfuron accounted for $>$80% of radioactivity recovered 24 h after application for ROX and RS. RS and ROX plants were treated with 1 to 64X labeled rates of three ALS-inhibiting herbicides, and 1 and 2X labeled rates of five non-ALS herbicides to determine whole plant response. The 1X rates of imazethapyr, nicosulfuron, and primisulfuron reduced ROX plant dry weight $>$64%, while 64X rates reduced RS dry weight $<$13%. Fluazifop-P, glufosinate, glyphosate, quizalofop, and sethoxydim 1X rates reduced ROX and RS dry weight $>$67%. ALS assays using ALS isolated RS and ROX shattercane showed that ROX and RS had similar ALS specific activities and total protein concentrations, while K$\rm\sb{m}$ values were 5.8 and 10.4 mM pyruvate, respectively. RS and ROX I$\sb{50}$ values were 231 and 0.025, 385 and 0.43, and 4630 and 13 $\mu$M for primisulfuron, nicosulfuron, and imazethapyr, respectively. Genetic control of ALS-resistance, determined using generation mean analysis, was primarily additive, with dominance and epistatic effects adding little additional control. When treated with primisulfuron, 5899 F$\sb2$ plants segregated into three classes, complete resistance, incomplete resistance and susceptible, indicating inheritance as a single, incompletely dominant trait. A 441 base pair region of the ALS gene encompassing Domain B was amplified from RS and susceptible shattercane (SS) DNA samples by PCR using primers derived from corn sequences. Shattercane DNA sequences were 99% homologous to known corn sequences. A Val to Ile change occurred in RS and SS, while a Domain B Trp to Leu change only occurred in RS.
Subject Area
Agronomy|Molecular biology
Recommended Citation
Anderson, Daniel David, "Physiological and genetic attributes of an acetolactate synthase resistant shattercane (Sorghum bicolor (L.) Moench) biotype" (1998). ETD collection for University of Nebraska-Lincoln. AAI9839139.
https://digitalcommons.unl.edu/dissertations/AAI9839139