CaHAM is autoregulated and regulates CaSTM expression and is required for shoot apical meristem organization in pepper

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• 作者：Rakefet David-Schwartz ; Yelena Borovsky ; Hanita Zemach ; Ilan Paran ; ^{iparan@volcani.agri.gov.il}
• 关键词：HAIRY MERISTEM ; Pepper ; Shoot apical meristem ; SHOOT MERISTEMLESS
• 刊名：Plant Science
• 出版年：2013
• 出版时间：April, 2013
• 年：2013
• 卷：203-204
• 期：Complete
• 页码：8-16
• 全文大小：2053 K

文摘

The angiosperm shoot apical meristem (SAM) is characterized by tightly organized cell layers and zones. The SAM's organization allows it to maintain its indeterminate nature while producing determinate lateral organs. Alterations in SAM gene expression partly account for the immense diversity in plant architecture. The GRAS protein family gene m>HAIRY MERISTEMm> (m>HAMm>) is an important regulator of SAM organization in m>Petuniam> and m>Arabidopsism>. Here we describe m>CaHAMm> loss-of-function pepper mutants characterized by an arrested SAM following the formation of several leaves on the primary stem, complete inhibition of axillary meristem development, an expanded tunica domain and trichome formation on the SAM epidermis. m>CaHAMm> is expressed in the periphery of the SAM and in the vasculature of young leaves throughout plant development, reaching its highest level in the reproductive growth stage. Analysis of the effect of m>CaHAMm> loss-of-function on its own expression showed that m>CaHAMm> is negatively autoregulated. Furthermore, m>CaHAMm> negatively regulates the expression level and pattern of pepper m>SHOOT MERISTEMLESSm> (m>CaSTMm>), which is required to maintain the SAM in an undifferentiated state. We conclude that m>CaHAMm> is regulated to achieve adjusted functional levels and has a conserved role in controlling SAM maintenance, organization and axillary meristem formation.